I tried manually changing the FPS with Cheat Engine, surprisingly it worked well, and was actually quite simple to do. I tried the .CT file for download and the method used to generate it in case an update causes the file to stop working (since the directory where the FPS setting is located doesn't appear to be protected, I didn't bother to track pointers), but the steam blocked the download, so...only search the address manually with the inscructions bellow, save the .CT file and enjoy.

⚠️ You need to unlock at least one cutscene in Theater at main menu, and have installed the cheat engine tool on your computer.

0. in the game's graphics settings, set "maxfps = 60" and "vsync = disable"
1. in the Cheat Engine, Search the first scan with the value 60 and value type seted to float
2. in the main menu, go to Theater and start any cutscene
3. in the Cheat Engine, Search the next scan with value 30. The address we are looking for will be the only integer among the floats in the list

• ⚠️ If you define in game's graphics settings "maxfps = unlock", the option defined manually in Cheat Engine will be ignored
  
• The FPS value in Cheat Engine will not result in good frame rate synchronization when above 59.93 with freesync. Enabling vsync of game settings and set the FPS value in Cheat Engine with 60 is the easiest way to get around this, but if you monitor has frame rate more than 60, maybe you may need use freesync, and set manually the FPS value that results in a value equal your monitor refresh rate in game.
  
• Use the graphics card vsync instead the vsync of game's graphics settings for better results and less ghosting, but maybe you will still have to search manually the FPS value that results in a value equal your monitor refresh rate in game.