An install on a fresh Ubuntu 22.04 ARM64 system was a bit bumpy:

• Ubuntu has Python 3.10. LNBits uses SCSS which uses collections.Iterate. The collections.Iterate module was deprecated in 3.10 and moved to collections.abc.Iterate.
• Therefore make sure you don't skip the step that instructs to install Python 3.9 from the deadsnakes repo.
• As an extra precaution I've updated update-alternatives on that system to point Python to 3.9.
• Documentation doesn't make clear but you need python3.9-dev (and build-essentials) to compile some dependencies.
• The build.py file fails under poetry complaining about scss. In my case running it outside of poetry finishes just fine. Other people arent reporting same success. Perhaps the update-alternative made a difference.

Anyway, sorry for the info dump. I thought it might help.