The color pattern indicates that the video needs to be re-encoded to play on proton, in order to get them you need to have shader pre-caching enabled on steam (settings > downloads) AND the game has to have been played by enough people for the shaders to be validated server side and then re-encoded, after which it will be autodownloaded for people who have the game installed.
in that case, I'll have to wait for more people to play it, as I've already got both shader options ticked.
proton experimentalx1 2024-12
Compatibility Report
System Information
I confirm:
Symptoms
Video playback error
Reproduction
At the launch of the game



Race preparation :
in game
I don't know if it's relevant to report video problems on demos, if not sorry