@jens It's a matter of priorities. There are things which are absolutely important (child, health, other humans) and those which are less so (work, projects, hobbies, etc.).

What helps me is to think long-term: what does a week of time spent on "X instead of Y" in a life of a human being make in the grand scale of things?

You don't need to forgive yourself - you did nothing wrong. I'd say "acceptance" is the right term to consider here.

With these thoughts, maybe you'd be interested to read a bit on (modern) Stoic philosophy.