It works! I didn't think so, but it works on the 680M iGPU, but you have to install ProtonUp-Qt (I used flatpak), select the installation for your client (steam, lutris), download GE-proton9-27.

Once you've selected compatibility for all games in the steam settings, just go to the properties of the game you want to play, go to compatibility, check the box and also select GE-proton9-27. Yes, you have to do this process, to activate compatibility for the specific game, in order to start playing with 680M.