I was pretty successful doing the terminal commands necessary to make flatpaks work on Ubuntu in recent memory, as out of the box the distro is Snap centric. Its odd you had so many issues on a fresh install of Ubuntu. Oof, sounds like my legendary problems with Arch.

Yeah, Mint requires some workarounds on older hardware. Its possible, but, probably not worth it unless you’ve got a burning desire to use Mint on that hardware.