I run Silverblue on 2 devices (my main computer and laptop) for half a year. It works and I didn’t have any major issues with it. Though as you might have experienced with other immutable distros, some things like configuring gdm might be a bit more work. But for most things there is a flatpak. The only software that couldn’t be installed that wat was my vpn.
If you want to try out something new, NixOS or Guix might be more up your alley



In Belgium at least it is illegal to circumvent copy protection. This isn’t even exclusive to the US, so I’m not sure where you got that idea from. So it is perfectly legal here to rip a cd from the public library but not necessarily for a Blu-Ray you bought
Edit: dvd’s can have copy protection so in that case it would depend on the specific dvd