I will write you things that I did and managed to beat the game (I play on Windows 11).

1. Download the missing files that are included in other instructions:
- audio_german.rcf
- skuinfo.p3d
- cementfiles.p3d
- audio.p3d
- enable_dlc.rcf

2. Download the mod from nexusmods called:
- Prototype2Fix - CrashFix - FPSFix - FrameDouble fix

3. Find the prototype2.exe file in the game folder. Right click on it and select properties. Go to the compatibility tab. Select the following options:
- Run this program in windows 8 compatibility mode
- Disable full screen optimizations
- Run this program as administrator
Finally save and you can enjoy the game.

Any order of steps. It may happen that one of these things is enough. For me was required to do all three things.
I hope this helps you.