I’ll provide another option that I hope will make you less concerned.
The box I’m using right now is one I use for QA (Quality Assurance) testing installs, and it contains the following systems
- Lubuntu 20.04 LTS (still supported)
- Lubuntu 22.04 LTS (still supported)
- Lubuntu kinetic (what will be Lubuntu 22.10 on release)
When Lubuntu 21.10 reached EOL; that system of mine contained a number of manually installed packages (ie. packages I’d added, eg. I like clementine for playing my music which isn’t a default for Lubuntu, etc), let alone my files (eg. my music). I already had a Lubuntu 22.04 system and had no benefit of having two of them, so I used the install to perform a QA-test install (called Install using existing partition in our testcases) to turn the EOL 21.10 system into a kinetic one. Post install I checked my music files where there & used my favorite clementine music player to confirm that (checking it & my other manually installed packages were auto-reinstalled during the install, and yep… I’d re-installed the system, my 21.10 system had become kinetic (22.10) without loss of my music files or manually installed packages. IF you have problems with release-upgrade, this is another alternative open to you, but as I tried to express in my last comment - I can’t see this as being necessary (though as it’s far faster! I have on occasion used it because I’m in a hurry too)
You no doubt know I’m not willing to give guarantees, as I have no idea on what Lubuntu will look like in 2024, though we’re working on that already given Lubuntu 22.10 is the first of the 3 non-LTS releases we make in the two year full-development cycle that started after 22.04 was released (18.10, 19.04, & 19.10 were steps towards 20.04; just as 20.10, 21.04 & 21.10 were steps towards 22.04; each full development cycle that takes two years consists of 3 non-LTS + the final LTS; each of which is six months). None of us have crystal balls or can see the future, currently we’re limited to opinions, and I’ve given mine as best I can.
Note: If you want more details about the install type I was mentioning, look at the link I provided on this site, though I’ve written about it elsewhere too (askubuntu, ubuntuforums etc) as the ability to re-install (repair Ubuntu used to call it) is something I love about Ubuntu’s installation. It works with ubiquity and calamares on Ubuntu ISOs currently; it’s intended to be on the canary installer too (what will replace ubiquity), but I’ve not had any success there yet in QA, but that should change with time.