So I have backup accounts on fedia.io and piefed.social

But when I left spez's site for the fediverse, I recreated some lost content (while it was still fresh in my head) and added a bunch of new content to kbin.social - AFAIK with ernest MIA and no way to reach an actual admin of kbin.social my new content is now gone.

That was a very discouraging experience. Since then I decided I wouldn't return until I could set up my own single-user instance - as owning and controlling my own instance largely means I always have a copy of my content, no matter what happens elsewhere.

I wish piefed.social (which only fully opened this year in Jan IIRC) had been around earlier. The lead developer of piefed is really helpful and responsive, and created a lot of documentation on how to run your own instance of pyfedi - including how to set up your own at-home instance via something like ngrok. Basically you get a HOWTO guide on how to do this. Compare with the complexity of getting a Kbin instance up and running in the early days...