Randomly it pops up saying something about an assertion failing on wine.. trying to get that to pop up again.
Hello @K1D77A, we're using one issue report per unofficially supported game title, so I've gone ahead and transferred this issue report to https://github.com/ValveSoftware/Proton/issues/8300#issuecomment-2583694013.
Compatibility Report
Marvel Rivals
2767030
System Information
I confirm:
Symptoms
Game launches, launcher opens and then

I can't upload the proton_log its 16gb...

https://dpaste.com/BQY4PRPU8 This is the first 1000 lines
https://dpaste.com/96FF893XX This is the last 1000 lines
Reproduction
Launch the game, then launch game in launcher.