Unfortunately, deleting emulators might be irreversible, so consider hiding instead. To hide unwanted emulators from your Recalbox 8.1.1 main menu, you can either remove their ROMs from the corresponding system folders within the "share" drive, or (if your Wiki mentioned it) edit the "menu.conf" file located in the "Share_Init" folder (accessible through File Explorer on your connected PC). Remember to refresh the game library after making changes. Hope this helps!