I’d suggest hachyderm.io then.

Tech centric, run by a co-op that’s also trying to be a general tech co-op of some sort currently starting some sort of software project. Run very professionally by mastodon standards. They use GitHub issues for lodging problems, issue monthly reports about things, have documentation etc, and, culturally speaking, try pretty well to be the inclusive kind of tech-centric (IE, queer, trans and BIPOC people are at the top level of the co-op). I’ve been on there for a while and never had a performance issue of any sort.

https://hachyderm.io/getting-started

https://hachyderm.io/about

https://community.hachyderm.io/docs/

The parent co-op organisation: https://nivenly.org/ They also have a discord which isn’t a bad tech place to hang out if you’re interested