So the rabbit hole extends outside the codebase and IMO won't help users who are not upgrading from an older Ubuntu install. (Did you upgrade or install fresh?)

For instance, it's not feasible for the everyday chirp user to collect all of the dependencies needed for chirp to run on Ubuntu 20.04 from a fresh install because many of those packages aren't in the focal fossa repo.

For instance, try to apt install python-libxml2 python-gtk and you may see a message like "couldn't find package xyz but is referenced by another package" from apt.

Tony.