Edit: And in the end, it's back to good old Fedora with Xfce. I guess I'm an old man, fixed in my ways. Haiku was interesting, but not nearly as stable as needed. OpenSuSE with Xfce was rough, it requires more polish.
I've been a Fedora Linux user for a million years by now, and I haven't touched any other OS (outside of Windows 10 and 11 at work).
Lately I got a refurbished ThinkCentre from ca 2018 (7th generation Intel i5, 16GB RAM, Intel HD 630). The initial idea was to use it as a media PC but the small form factor ended up not being small enough for my living room.
Now I'm thinking of using it as a desktop PC for a while, to see if it can make my laptop be a portable machine again instead of always plugged, always on. If it doesn't work out, I'll use it as a home server.
Since this is all an experiment, I want to give a new OS a shot before I settle for the familiar Fedora.
OpenSuSE is the first on my list, but even from the LiveUSB I noticed that the software selection is more limited than I'm used to.
I'm thinking of giving HaikuOS a shot as well.
What else has been going on in the world of free OSes since 2007? What's one that you are excited about?
For true freedom and to challenge yourself, try OpenBSD. For something easier, try GhistBSD since it comes with a GUI desktop.