I had 2 issues :

* Graphics would freeze after a few seconds. Sound still plays. If I alt-tab, the graphics unfreeze and play if I don't release Alt.

I fixed it by ticking "Disable fullscreen optimization" in the compatibility tab.

Unfortunately, I could not fix this issue with the widescreen patch.

* Cutscene had very out of sync video and audio

I fixed it by forcing VSync in Radeon settings for the game. It is BGE.exe
I didn't need run.exe to take CPU cycles. It made no difference.

If it can help anyone.

Hey, thanks for you report. Helps me, imho, but I'm not sure =)
I've struggling with different problems more that 2 hours...

So on my PC Win10+Ryzen1600+RX580 this solution works:
- removing records with regedit and fully reinstalling game
- run 'Settings' and put all settings on except 'W buffer'
- set Compatible mode for BGE.exe as for WindowsXP and check 'Disable fullscreen optimization'
- install Widescreen fix by nemesis2000 (https://www.pcgamingwiki.com/wiki/Beyond_Good_%26_Evil#Widescreen_resolution)
- add BGE.exe as game into Radeon Gaming Center, disable most default settings, override Antialiasing and set wait for Vertical Refresh always on

Now seems it works pretty smoothly. But I'm not sure about grafic quality, antialiazing and so on =)