I now use syncthing for the .git directory, excluding HEAD file and a few others, between my few devices and a vps on hetzner.
Most of git is append only immutable blobs - just sharing these between devices just works for me. "users" and authentication is handled by syncthing.
I have pre and post hooks to make sure no device tries to change HEAD of branch owned by another device, just to be safe, be it hasn't been activated once yet.
I read the piece, looks cool, but it merges Dockerfile with docker image?
If instead of using Dockerfile they would have a direct build of the image tar file with something like nix then it would have been easier, though admittedly mildly esoteric
I've given the following exercise to developers in a few workplaces:
What's the complexity of computing the nth fibonacci number? Make a graph of computation time with n=1..300 that visualizes your answer.
There are those that very quickly reply linear but admit they can't get a graph to corroborate, and there are those that very quickly say linear and even produce the graph! (though not correct fibonacci numbers...)
So 4.6min, i.e. 4:36