It’s my choice but Arch and its derivatives look like the trend like CachyOS which is #1 right now on visits on distrowatch. Also I’ve heard Google use Debian as gLinux and I feel many other giants also use it and sponsor it and I’m not comfortable choosing it as my distro. Can the sponsors togethwr with students or any other interested use it for their PCs, either coding or ordinary use? It strictly promotes free but worried about giants and sponsors.
ymmv, but debian has always been near perfect through upgrades for me: even a recent buster -> bullseye -> bookworm -> trixie went smoothly.
issues usually arise from not maintaining a clean debian stable install (e.g. you were using backports or lots of 3rd party repos). if those are cleaned up prior things still usually go well.
not saying you didn’t have issues, but in my experience with with lots and lots of debian systems, upgrades have been 99.9% cakewalk.
the same goes for any distribution not just debian. installers and upgrade processes cannot possibly account for the infinite number of unexpected things they could encounter. the more you go ‘off book’ with third-party repositories, backports, manual configuration changes, manual package installs and what-not, the greater the chance for having ‘issues’ with version upgrades.