Plenty of older games only seem to work with certain versions of Proton/Wine, DXVK etc. There are projects like Bottles which let you manage multiple Proton distributions https://usebottles.com/
That's true but in Steam on Linux there's a dropdown menu in the settings that lets you choose the Proton Version. And tools like protontricks can add additional wine/wine-staging/proton versions that would show up in Steam.