Out of curiosity I checked what the process is to port Ubuntu Touch to an unsupported smartphone. Apparently one of the requirements is that it needs to have an existing source-available port of LineageOS 12 or 14. Which is a bit limiting, of course, and I wonder why that restriction is in place.
Ubuntu Touch/UBPorts is intended to run on kernels that have been patched for AOSP, with libhybris being used for driver support. The LineageOS project (well, individual device maintainers most of the time) does all the dirty work of getting the kernel to build, and run something like a baseline AOSP environment on the device. I'm pretty sure that requiring support from the mainline kernel would be a lot more limiting.
Even with a Lineage device tree ready you really don't want to try to port it, trust me. I've spent weeks to try to port it to my old Galaxy S4 and just gave up at some point. It's very difficult even with the work done by Lineage.
Plenty of issues, so first just setting up the environment is already quite complex, then I had to do various patch to the device tree to get the test image working and the test image kernel booting. The only thing I managed to do was getting a shell and having the vibrator working, apart from that, all the other libhybris tests were failing with segfaults and I could not understand why.
> Would a newer phone have worked better?
Difficult to say, I'd say that each phone is likely to have issues in different ways.
