Strawberry for music transfer and GPodder for podcasts works perfectly on my iPod Photo, although both of them do have slightly clunky interfaces that may take a bit to get used to. Rhythmbox also works great, although I haven't been able to get it working on my current Arch setup yet.
If you aren't trying to run anything too crazy (like AMD HIP compute, HDR, really bleeding edge hardware) I would probably recommend giving openSUSE Tumbleweed, Fedora (only the regular GNOME version, for some reason KDE spin was buggy in my experience), and Pop OS a test drive off live USB drives. Each has their own merits, so it's worth trying all of them. In terms of NVIDIA support, I personally do not have much experience with NVIDIA cards, but when I was helping a friend format an iPod Fedora booted off a live USB on an RTX 4050 laptop with little fuss, and if you install it gives options for installing the full proprietary NVIDIA drivers. I know there is also an NVIDIA installer option in YaST's software manager for openSUSE, and Pop even has an ISO with the drivers baked right in for full compatibility. However, your mileage may vary, although I have heard the whole NVIDIA situation is pretty good right now as long as you have the proprietary drivers installed.
Finally got tired of my Windows 11 install, and I considered a Linux move. For years and years, I tried to move over, even all the way back in the Ubuntu 16.04 days, even daily drove for a few months, but there would always be something that would make me move back (including but not limited to HDR, support for my old iPod, Outlook calendars, so on). However, on my most recent attempt (running Arch and KDE) things just... work? Yeah, some command line trickery is needed for stuff like HDR gaming (and turns out the screenshots work now, they just get downsampled to SDR by Steam), but this works so so much better than my previous attempts to move over. In recent years, the experience is just so much more polished than it used to be. The situation is no longer "that won't work", it is "you can do that, with some minor tweaks". All my Steam games work nearly perfectly, with only a few changes like Proton GE needed. There are now even improvements like how text on my QD-OLED monitor (which is notoriously fuzzy on Windows) is crisp and clear, or how my Xbox controller's screenshot button works over Bluetooth on Steam unlike Windows which ignores the button entirely over Bluetooth. Things are really looking up!
openSUSE Leap - YaST is the greatest thing since sliced bread, and works great on command line over SSH. Yes, sometimes installing some software is difficult, but generally most stuff you would want is there and a lot of stuff runs on Docker anyway now. Very stable too, have had nearly zero issues.
Yup, was using Spectacle, behaviour was similar to your description. I guess maybe the HDR highlights just got more blown out on higher brightness displays?
Just wanted to find out if there was any progress in terms of screenshots when using gamescope and KDE 6. Last time I tried (running Arch and with an AW3423DWF monitor with HDR 1000), display support worked, but screenshots seemed insanely washed out and generally broken, which was unfortunately a make it or break it feature for me. Has anyone got a similar setup that they can try it out on?