If you are launching Marvel Rivals for the first time via Steam Remote Play, the game might appear stuck or show a black screen (as shown below)..
This happens because the Terms of Use popup window is not visible through the Steam Remote Play stream. You need to accept this agreement manually on your VPS desktop.
How to fix it:
Go to your Browser -> AppOnFly - Gaming Session
Click "Open Management Session" button to open your session
You will see the Terms of Use and Privacy Policy window (as shown below).
Click the green I Agree button.
Once accepted, the game will load, and you can continue playing via Steam Remote Play normally.