To turn off on-screen overlays in RetroArch, navigate to Settings > On-Screen Display > On-Screen Overlay and toggle Display Overlay to OFF. For a faster method while in a game, open the Quick Menu (F1), go to On-Screen Overlay, and turn it off. Be sure to save overrides to keep them disabled.
Methods to Disable Overlays
Permanent Solution (Global):
Go to the main menu > Settings.
Select On-Screen Display.
Select On-Screen Overlay.
Toggle Display Overlay to OFF.
While in a Game (Quick Menu):
Press F1 (or your designated hotkey) to bring up the Quick Menu.
Select On-Screen Overlay.
Toggle Display Overlay to OFF.
Save Settings: To ensure they stay off, go to Quick Menu > Overrides and select Save Core Overrides or Save Content Directory Overrides.
Additional Tips
Hide Overlay When Controller Connected: Under Settings > On-Screen Display > On-Screen Overlay, you can enable "Hide Overlay When Controller is Connected".
Adjust Opacity: Instead of turning them off, you can change the Overlay Opacity to 0% for a cleaner look.
Remove Input Graphics: To keep the bezel but hide the button graphics, turn off Show Inputs on Overlay.