In case of merge conflicts you might have to update the content_hash based on the merged result (if not taking one alternative completely).

There appears to be no command to update/verify/rewrite the lock file without updating it, is there?

I've tried pdm lock, which does not have --no-update like e.g. poetry. I think this could be a good option here also?

(I've also tried pdm update --update-reuse, but it would still update versions.)

As far as I can see it gets done currently implicitly with pdm install:

Lock file hash doesn't match pyproject.toml, regenerating...