My station is not working outside stops. I can set stop but passenger cant get on/off on outside stop. How can I fix it?

Yes, that is the LOD. Otherwise you would see an automatic generated mishmash. That is what happend if there is no LOD.
The alternative would be an LOD with 10k tris if I hadn't make it flat.

Is there a LOD? I'm seeing a blank white shell when zooming out. (playing vanilla)

Would like to see you put the roof on this version on your monorail version of this asset. I tested the monorail version of this asset with a prop version of the monorail vehicle I want to use, and the roof around where the trains enter the station is too low for it on that one; the higher roof around the entryway in this railway version would be perfect for the monorail version of the asset as well.

No, but it doesn't have to either. An old mod can also work with a newer version of the game without having to make changes to the mod's code. If it works or not depends on how big the changes of the game are.
Okay, I thought so because I didn't have the negative rating before your comment.

ETST is not updated for Skylines 1.16.0-f3 ... or I'am wrong ? ... And I did not gave you any rating.

Who said ETST is obsolete? You need to subscribe and enable ETST to have elevated train station tracks for this station.
Is that why you gave me a negative rating?

ETST are obsolet ... how does it work ?