The graphics preset should be around Low (or custom if you want Volumentic Fog, Motion Blur, Depth of Field and/or Real-Time Reflections). You might need FSR2.1's Quality or alternatives.

Due to some minigames (primarily SEGA Arcade games) being tied to game speed, it's highly recommended to set the in-game framerate to 30fps, as it'll switch to 60fps. You can still use SteamOS's Framerate Cap to 30fps or 40fps for the vast majority of cases (no pun intended) but I suggest setting in-game framerate to unlimited for it.