Hmmm, here are my thoughts:
1-generally, anything that works on Windows 10 will work on Windows 11.
2-I forgot the track limit on PT Intro. Have you considered PT Artist? Its $9.99 per month or $99 per year.
3-as with any update(small or large), you don't need to fear if you have a backup strategy(and you SHOULD!). Drive imaging is the least you should be doing. Another option would be to clone your current C: drive to another similar drive, install the clone and update it(leaving your current C: drive untouched and unchanged)
4-if you can't afford PT Artist, might you be better off with another DAW such as Reaper or Cakewalk by Bandcamp? Those 2 are free to try(Cakewalk is just plain free) and both are very capable programs with none of the limitations of PT First
Of course, before diving into anything new, you would need to open each of your old song sessions, consolidate all audio tracks, print any instrument tracks and export the files to separate folders so you could import the files to another DAW(which is something worth learning how to do anyway)