I am not on youtube, ♥♥♥♥♥♥♥, discord, twitter, splatter or whatever shameless nonsense you are used to seeing plastered across these guides. This is short and to the point, I don't want to waste my time or yours and I'm not trying to sell you something for ad revenue.
There will be no pictures or videos, just words and the deep and mysterious nexus that is your imagination.
This is a not pretty guide and I offer you absolutely no apologies for it.

Useless Melee Weapon: The melee weapon consumes three things; carry weight, stamina and time. You should never use it as you can dodge behind them and stab them in the back with a knife or floor them with a shot and stab them in the face. This is a far quicker animation than the melee one. Both actions reduce stamina but only the backstab requires you to have stamina, you can finish a floored zed with zero stamina.
Don't ever pick up a melee weapon from a drop pod.

CLEO Shotgun: Some people think the CLEO blast rifle is the best weapon, its ok but not optimal for daybreak. You are facing an army and you need a weapon with spread, power, knockback and good ammo consumption. Thats the CLEO shotgun, it will kill most enemies other than the jug in one shot and floor anything it doesn't. Thats where the knife animation comes in handy for armoured zeds.

Remote Rocket Pod: This is the most powerful item in the game. Anything in its area of effect dies, pure and simple. You need this for wave 5 for the two blood jugs because you need them dead fast so you can kill the hordes coming in. If you don't have this try using a minefield or, at worst, a remote explosive. WARNING: Do not try to put one directly underneath a horde or jug. It will place it off your target and potentially miss entirely. Try to put it alittle to the side so it remains in the area of effect. This has cost me many rocket pods.

Two NPC's with hordebreakers: You can do it with two guys with shotguns, I've done it. I'm telling you not to and that they are worse than useless. Guys with hordebreakers take care of business and ferals... usually.

Paranoia is good.
First off, your primary thought here should be "If I don't know theres something behind me, there probably is." Guns make sound and sound can attract zeds away from attacking the walls. If you think something is behind you dodge backwards, shoot or stab them in the back. Snacks and pills may be occasionally handy to deal with the consequent stamina drain but you will almost never need them. This is why ditching the melee weapon is good, saves you stamina and more important; time. Also; RUN WHILE YOU RELOAD to avoid interruption and frustration.
Oh and you can repair walls in gas clouds by dodging into them and interacting. Time is more valuable than health. You can get medkits, you can't get time machines.

The calm before the storm. (Waves 1 and 2)
The time at the start where you have to prepare is the most important. You need to go through every box, take it all out and drop it in accessible places beyond the barrier in an organised fashion as quickly as possible. It will be your job to predict what you need, when you need it and what you should put down so it doesn't take up space. Empty the stormbringer of its ammo for use with the hordebreaker on wave. I *highly* recommend putting the CLEO ammo and bandages found here near the tech for wave 5 and beyond. This will be your emergency supply. Any other CLEO ammo you find in supply drops you should put where you like outside the walls.
You will be using normal shotgun for the first and second waves, hordebreaker for the third and the CLEO shotgun for anything past that.
You should not be repairing after either of these waves.

Cleo loves you. (Supply Drop 1)
After the last zeds of the second wave dies your organisation skills pay dividends; you're going to make repairs then run like crazy and collect ammo, explosives, medkits and bandages after every wave. You're going to drop all your stuff, get all that, come back, quickly organise what you don't need, pick up what you do. Snacks and pills, although pointless at first glance, do have their uses for getting from one side to the other quickly and backstabbing armoured guys. Use your own discretion.
This time you will get snacks, bandages, cleo ammo, shotgun shells, repair kits and some fire bombs. Take everything but the shotgun shells, you're done with that rusty thing. One of the pods will drop close to you but salvage that one last. You should have just enough time to arrange everything and equip the horde breaker.

Open Season. (Wave 3.)
For the third wave the hordebreaker should be set to single shot but when the juggernaut arrives on the third wave switch to burst and empty it into his face. Do not be shy with the ammo but make it last the round. You will not be using this gun again. Once its done, drop it and pick up your CLEO weapon.

Cleo is the bomb. (Supply Drop 2.)
More or less the same as before except this time you will find six remote explosives. Put them to good use.

The storm before the hurricane. (Wave 4.)
For wave four its pretty hectic but manageable, use explosives to kill jugs, use fire bombs to blow up gas clouds, use your gun to kill things as fast as possible. You may find snacks and pills useful this wave. Repair as soon as the last zombies hit the ground, do not heal.

Cleo Hates You. (Supply Drop 3.)
The only ammo you will find in the supplies is in CLEO pistols, you can empty them into your inventory without having them in your inventory. The rest is mostly medkits, pills and repair kits. Use the pills and the medkit in storage. Take all the good stuff, run back, pick up ammo, pills, one batch of fire bombs, *definitely* pick up rocket pods you left at home or whatever lesser item you selected.
Prepare for the hardest wave.

The hurricane. (Wave 5.)
What makes wave 5 so bad is the overwhelming numbers you're up against versus the total lack of raw firepower you need... without the rocket pods anyway.
Stick to what I've told you so far and you're good. Kill Jugs with the pods and gas clouds with fire bombs but even if you do this theres a possibility they could break through. If this happens your primary strategy will be to clear the ones that are on the technician while using your now internalised paranoia to dodge zeds. The shotguns power and spread really shine here and the tech is immune to friendly fire. Time your shots, reload when you can, do whatever it takes.
When the last one goes down you have got past the worst of it... but there is still more.

Its Christmas. (Supply Drop 4.)
The supply drops from here on out are extremely generous. This time you will find ammo galore, four mines, three remote grenades, some fire bombs, pills, etc etc. You won't be able to take it all. Prioritise explosives over ammo. Use them the way you have learned. Lay three sets of mines along the sidewalk and one inbetween the technician and the wall. Be aware that you can be knocked over by exploding mines so be careful... also if you launch the mines directly beneath a jug they all hit and explode on him killing him instantly. Ferals are also killed instantly by mines. If you have survived wave 5, repaired the walls and got the supplies you want then you are in very good shape and you are close to winning this. Keep in mind though, all it takes is one feral and three moron NPC's to ruin this.

The Swarm. (Wave 6.)
Wave 6 is mostly zeds with afew jugs thrown in but nothing you can't handle with your remote explosives and mines. The pills you found in the drop will help you stay ontop of things. Do not be shy with the fire bombs, they will have little use after this wave.

The Last Drop. (Supply Drop 5.)
Cleo ammo, six remote explosives, one rocket pod, two mines, some firebombs and a CLEO smg. Leave the fire bombs, you will see why. The CLEO smg on the other hand is abit of a dark horse that offers you two options. If you already have plenty of ammo you can load it into a single jug basically giving you a free kill. If you're running low you can head back, drop all the ammo you have retrieved and then empty the smgs ammo for use in your CLEO weapon. The choice is yours.

Jug-ocalypse. (Wave 7)
Wave 7 is afew zeds with a crazy amount of jugs and ferals. But theres good news, when jugs aren't coming your direction theres an opportunity to quickly blast away afew zeds and repair that wall while stragglers helplessly pound on it then hop back over to put shells in their faces and turn to the coming jugs.
The wave ends with two jugs, I always try to save my rocket pod for them and lure them closer together but do what you will. If you have gotten to this point I'm fairly certain you can handle them.
Oh and one more bonus; you don't even have to kill them all. You just have to survive until the wave ends. I mean, you definitely should kill them all and I will see it as a personal insult if you don't but that is an option. A highly dishonourable option that we will all judge you for.

An ever expanding list of things I have noticed as I grow more experienced with this mode.

- When you have a spare moment before a wave make it so there are exactly five repair kits in your inventory. It will usually save you having to drop one during the mad dash for the supplies.

- You can use bandages and medkits while they are in a container. This applies the healing effect but not the animation. The same is also true of stimulants, even if you don't pick them up they can make the journey less exhaustion prone.

- Gas clouds might hinder movement but theres nothing stopping you from repairing a wall in one. Time is usually more scarce than health.

- Pills are extremely useful for mobility and when facing an abundance of armoured zeds. They allow you to backstab them all in quick succession and run to the next threat. This allows your NPCs to focus on softer targets.

- Switch quick items before attempting to activate a rocket pod or remote grenade. This eliminates the possibility of unintentionally using another one and, for some reason, seems to make it go off faster.

- Allowing bloaters to reach a barrier can be beneficial if you are facing massive numbers and have an excess of fire bombs. You can ignite the gas and solve two problems with one explosion. This is the only time fire can potentially be useful against a juggernaut.

- If it comes between a choice between killing a jug or killing zeds on your technician its usually best to go for the zeds while holding the jugs attention.

What now?
Now you have to do this over and over again to get all the unlocks. But when you get all the unlocks the fun doesn't stop there because all content from this game mode, including red talon operatives, costs prestige points... that can only be earned through daybreak... which you just did fifty times...
K. THANKS DEVS. THANKS. THANK YOU. CHEERS. NICE ONE. GOOD JOB. 10/10.

Anyway, this has been a not pretty guide. If there is anything you feel I should add let me know, otherwise you are now more informed than you were and I have raised awareness of how not fun this game mode is.
Time and effort well spent I'm sure you will agree.

UPDATE: I did it. I have all seven red talons I wanted with the exact quirk skills and hero traits I wanted them to have.
I am so done with this game mode its not even funny.
Oh, one final tip. If you don't get a red talon with a quirk skill you like you can just exit the game. When you resume the mission will start again with a new red talon operative.
Alright, good luck. Bye. :-)