I can tell you that I do a lot of audio work myself and have done for years. I had dabbled with the Linux desktop many times but this most recent time I put Ubuntu 18.04 on my primary machine back in 2018 and have actually been incredibly happy with it. As you noted, with Jackd2 and PipeWire for high-quality audio work Linux is definitely right there and in some ways better than Windows. My desktop now runs Ubuntu 20.04 with the -lowlatency kernel and for both my audio work and the little bit of video editing I also dabble in it's been amazing, solid, stable and predictable.
And I don't know if I'm just not a demanding gamer, but just about every game I've thrown at this setup has worked great as well... now granted I don't do a lot of multiplayer and every game I have these days is on Steam... but even big AAA releases seem to just work most of the time. In fact, most of the problems I have with games tend to be the small indie developers or the single developers. The only recent examples I can think of that required either fiddling or just plain didn't work for me were Exo One and Starship EVO... again, small studios. But even then a few updates later both worked straight out of the box and I have no issues with either now. Yes, most of my games run under Proton rather than native... but I don't typically see any problems with these running.
I will admit I run the proprietary NVidia drivers... but Windows users do too. So if you're a complete nut for "untainted open source" then yeah you're going to have a hard time... but having said that if you're going for fully open source why are you trying to get inherently closed-source games to work anyway? I do very occasionally hit performance issues with games, but they are vanishingly rare at this point and seem no worse than performance issues reported on similar hardware in Windows. I might not be getting the absolute maximum framerate out of every game, but over 60fps I am not sure I've ever actually cared all that much except for "bragging rights". The games look and move fine by my standards and I can play them. Maybe with my age my eyes just don't care all that much any more :) Simply put; my video card can drive my 120hz widescreen monitor just fine for everything I throw at it; why should I care about a few more FPS?
As for sound drivers, that actually tends to be a pretty solid support experience in Linux. Sound just isn't being developed or advanced the way graphics are; there's just no need. There's little that needs to be done with audio that really will make a significant difference to the finished product because human ears haven't changed and computers frankly were well able to do audio work decades ago. Sure, more CPU horsepower means I have more channels to play with and better DSP's can help make my final mix cleaner, but the truth is that the technology didn't plateau but certainly reached the "flattening of the curve" part of it development a long time ago and most new hardware is merely incremental improvements and usually actually using the same hardware with a few new interfaces attached. I literally can't remember the last time I plugged in a new bit of sound hardware and it didn't just work out of the box, even if it said it was for Windows and I couldn't find any specifics about whether or not it was supposed to work. In fact the only problem I have with Linux and audio is that I have so many inputs and outputs in my machine that every now and again it gets confused about my defaults and I find myself jumping on a conference call where noone can hear me or I can't hear them and I discover that it's trying to use some other audio device that's not immediately preferred for the meeting. Fixing that takes me 10 seconds in the Ubuntu mixer.