Steam starts Proton inside a container and runtime. Maybe those provide some special $stuff for those games.

Proton is basically just a version of Wine but Steam has other runtime apps like Pressure Vessel that work together making the game run. Don't know if Lutris has anything else than managing and running the apps in the Wine prefix with specified Wine version. This is as deep as my knowledge goes.

Proton is Valve's version of wine running inside a container specifically made for Steam, while Lutris is only using wine.

And the versions being used by Lutris and the version being used by Steam are not the exact same thing. If you use GloriousEggroll for example there is the proton-ge-custom repo for Proton, which is the one Steam uses, and the wine-ge-custom repo that Lutris uses.

I'm not even sure that the latest "GE-Proton8-14" and "Wine-GE-Proton8-14" are actually equivalent to each other. They were released two weeks apart and might be based on slightly different wine and/or dxvk versions since they are using whatever the bleeding edge git commits are, rather than actual stable releases (i.e. using commit #ABCD1234 instead of release version 1.2.3)

I think it is to do with the files steam adds, not just proton.

To get a pirated copy of a game to work I created a compat folder for steam games, put the whole game in there, then ran it from lutris and it worked. (I can’t remember exactly how I created the compat folder but I can update this comment later when I’m at pc if you can’t figure it out)

When running from lutris without the folder structure of steam compat files it had many visual glitches.

When running from steam it tried to attach some steam processes which didn’t work for the pirated game.