[nerdjon]

Unfortunately very much not the case.

There are still a lot of issues playing games outside of Steam, and not every game is available in steam.

As someone else said there are some issues with anticheat (but some do work).

It is also not unheard of for a game to have an update and it break the proton compatibility. Meaning anyone who wants to play the game has to wait for proton to update with a fix.

But also, not every game on Steam works either.