A few things to expect when playing Red Dead Redemption 2 on ONMO+:
Story Mode only
Red Dead Redemption 2 currently supports Story Mode only. Red Dead Online is not available yet, but we're actively working on supporting it in the near future.
Rockstar Games Launcher sign-in required
On first launch, you will need to sign in to your Rockstar Games account before you can play. This should only be required once.
Windowed mode on launch
This game opens in windowed mode by default. You can switch to fullscreen at any time from the in-game display settings.