It's true, I know from experience that running Linux on old SP's is not easy, I also have an SP5 and I installed Linux on it, it took me a long time, time that not many people are willing to give just to experiment with stuff. What I can say about it is that it's working amazingly well, after I installed the Surface kernel... my pen works ok, the touch is weird, you can't press with the tip of the finger, due to how it reads touches, but it's a work in progress. Now, I use an SP8 with Fedora KDE for university, which works great. It took me just a few hours to install, due to me tinkering before with the SP5.
In my opinion, you should give it a try on a virtual machine, just to try it before installing it directly, and just give it another go. KDE came a long, long way now. It's not perfect, but it works very well.
I'm happy to hear it. My first experience with Linux was Steam OS on the steam deck for one year. At first, I didn't get technical with it, but some time after I bought it, I started tinkering with the desktop environment and loved it. FF to recently, I had Bazzite. It was amazing, but it was a pain with the non-imutability of the system, then moved to Fedora KDE Plasma, and I love it. A very big plus for me on Linux over Windows is that I can play very, very old games on Linux, thanks to wine.