It may be pretty good for previous-gen games and hardware, and that too after various compromises.
Current and next-gen PC hardware will always be optimized for Windows first, with some technologies being straight-up limited exclusively to Windows.
Not that gamers are losing out on anything valuable, of course. I run Debian stable and spend quite a few times gaming on it, and it turns out almost all the games that won't run on it aren't games worth playing altogether. But this is an opinion of the negligible minority like you and me. The Consumers will obviously care for the latest.
The Steam Deck is, at least for Valve, a first-class citizen of its platform. Tons of money and effort has been put in to bring it up to Windows. It’s not quite there yet, but it is a lot closer than you’re making it seem.
No DLSS or ray tracing. Those might work if I imported the game into Steam; the it would use the Steam settings where I think they do work, from what I've heard. But I don't care that much about DLSS or ray tracing.
Otherwise, I think I've got the highest graphics settings, though I haven't checked them.
The only app still making me want Windows is Paint.Net. It really feels by far the best, if not say perfect, non-pro picture editor ever. I would even pay for really good (Pinta is quirky although indispensable) Linux and Mac ports. I also love Visual Studio but JetBrains Rider seems more than a match. Games indeed have ended being a problem long ago. Perhaps some latest and greatest games still are, I dunno. Have anybopdy tried something like Hogwarts Legacy or Baldurs Gate 3 on Linux?
BG3 works well on my new recent install of Debian Bookworm with nonfree sw on, Nvidia RTX 2080 SUPER, nvidia prop driver 525 or 535 I think, KDE Plasma set to Xorg (Wayland caused some flickering, supposedly bad interaction between Wayland and nvidia drivers).
I think I don't have advanced stuff like DLSS and HDR though, maybe I could if I did some tinkering.
Which may be another motivation for them to buy up so much of the gaming industry. They can probably justify blanket banning anyone playing COD on Linux in the name of banning cheaters.
Current and next-gen PC hardware will always be optimized for Windows first, with some technologies being straight-up limited exclusively to Windows.
Not that gamers are losing out on anything valuable, of course. I run Debian stable and spend quite a few times gaming on it, and it turns out almost all the games that won't run on it aren't games worth playing altogether. But this is an opinion of the negligible minority like you and me. The Consumers will obviously care for the latest.