I'll also add I only have so much energy in the day, and after a couple of years of fighting against problems I coudn't do anything about and managers who couldn't make the changes, and customers that wanted it now, I burnt out, and instead of spending a useless zoom meeting to work on an improvement I use it instead to make maps for the D&D campaign I am running.

While I've seen several examples of this being the only way to get out of never prioritized debt-cleanup that the team can't bother explaining to management in non-technical business-value terms. The reality is a sprint is always over-packed with stuff to do with zero room for side-projects and expecting people to work weekends on side-projects to solve company business needs is not exactly a sound strategy.

What one can do is is deliberately allot time to the team to work on any side-project as long as they are somehow attached to the business. There are ways to do this more organized, for example innovation-weeks or the famous Google-fridays.

That can work assuming the team isn't already overloaded. But when people are being asked to work 60h a week or more to accomplish their tasks, it becomes untenable.

That's exactly what I am doing and aside from a few wrist slaps people have been okay with such an approach. I always tell them I did this for a few hours during the weekend or while I was waiting our DevOps to resolve an outage these particular 2 hours the last Friday. Seems to work really well.