Does it work with wine/proton? anecdotal but even in apps/games where they make a linux port the wine/proton version sometimes works better.

I have Linux GOG games which refuse to run for one reason or another. Some outdated library, compiler, whatever that is not on a modern distribution.

If you want easiest future proofing, you gave to use the windows release.

The idea of running old Windows games definitely doesn't go hand in hand with Linux. And I think GoG simply has way more Windows experience, lots of work to do, and little realistic chance of tapping some huge market if they spent all the time you need to support 2-3 major Linux distros - especially when you need to offer things like Multi-player support as well on those, plus maybe game recording and whatever else the overlay offers (GoG Galaxy is not just a storefront).

Why not? My experience has been that old games run easier and better on Linux than Windows thanks to Wine and Microsoft's stupidity