tl;dr KB+M and no touchpad here so that might have something to do with it, I prefer more compact and colorful UIs, and different behavior between LMB and RMB.
I'm not a big fan of the Nautilus file manager, all the rows seem too big and too padded. There is no compact mode and from what I've read changing the default file manager is a big no-no in linux since the OS depends on it (and I did try to install Dolphin just to compare but the theme was unusable with bazzite). I can't even pin other drives to the left navigation pane, only folders? The monochromatic theme is neat but just makes it more difficult to tell things apart, gimme some color please yellow folders.
I know the no desktop decision is "since they always get cluttered anyways", but making me use a folder instead will just force me to use a cluttered folder instead, or more likely keep stuff in Downloads. At least with the desktop I can visually arrange it.
I miss the taskbar for switching apps. I do agree pressing the win/command button is neat and practical but sometimes I just want to switch to a different app on my second monitor using mouse only (or see notifications from it) without moving my keyboard hand.
Then it's the small things - I did install the clipboard manager gnome extension (because copyq doesn't work with wayland apparently) but it always opens it in a corner, not on my mouse location.
Systray - left and right mouse buttons do the same thing and doubleclicking does nothing? For example to open the steam window from it I always have to click it, go down to library and click again, this is the default behavior of RMB in other OSes and here it's the only behavior.
Minimizing something and then immediately alt-tabbing doesn't bring that window back up, some focus issue? Two monitors issue? Dunno but annoying.
It's been a while since I used ubuntu and popOS was only for a few days so maybe I was just mistaken, I remember it being somewhat comparable to a classic desktop at the time but it could have been that cosmic shell thing. And tbh until so far I thought cinnamon is gnome so it seems like I was just outright wrong about that one, thanks for clarifying
I'm definitely willing to try bazzite's gnome3 for a while, i just wasn't sure what's the default anymore and if it's bazzite doing something out of the norm or if the ubuntu based distros did.