Epic Games Services cannot open its window with SDL_VIDEODRIVER=wayland (but the game can run with it after the first initial setup), this also disables the online mode as it depends on Epic Online Services.

Also, on the first initial setup where you need to link your EGS account to steam for login, a window will pop up and you will not be able to click the screen with your mouse or the touchscreen on steam deck. On linux PC use the TAB button to select the menu buttons, on the Steam Deck, hold down the Steam button and use the trackpad to bring up a cursor to select on the menu