Can the pyc compilation step done by our normal package installers be made to treat this warning as an error so that it is forced into the package owners faces instead of overlooked because it was just something on stderr?

This syntax warning is absolutely the right thing to surface for _owners/maintainers_ of a given piece of code.  Their strings are wrong and their code quality will improve as a result.

It isn't the right thing to surface to _users_ of someone else's problematic code.  (though it does serve as a red flag proving that the owners of that code or person who pinned some dep to an old version haven't proactively tested with modern python)