I just tried the latest Ubuntu on an X1 Carbon and was disappointed. At first it was looking good, but then the warts started to show through. I could live with some of the problems, but I had to do some searching to learn that the reason Firefox scrolling was laggy was I was using a non-standard hidpi scale factor, the UI froze multiple times in just a few days, and it felt all around glitchier.
1. Maybe give Kubuntu a try. Have not used Gnome in many years now, but when I did, lag was a given.
2. Have you setup full disk encryption? Unless tweaked (thanks to Cloudflare kernel patches) dm-crypt will cause short system freezes.
3. Firefox is still an unfortunate story on Linux. Still no hardware acceleration enabled by default (and just in the last year, I think, made toggleable universally in about:config)
Thanks for mentioning the Cloudflare patches. While I had already read about that in the past, I wasn't sure what's the current status of their work. So I checked it out and was pleasantly surprised as their patches are included in the mainline kernel since Linux 5.9.
As a pro, at least, dual booting with Linux is still straighforward. I guess other OSes can't compete there.
I have to admit that otherwise its not all roses in Linuxland. Fedora for example, a couple of versions ago switched their upgrade peocedure to the awful download now, reboot system and wait for updates to complete. Basically upgrades feel like Window upgrades now. Maybe that's the way they want to "force" users to swith to Fedora Silverblue :)
Or, you could just install Debian. Then install all the windowing environments you find interesting. No "swap to Kubuntu" required, just start a different window manager. Hell, run all of them simultaneously on the same install using a VNC server.
