I ended up with kbin.social since I liked the interface, liked the roadmap and existing integration with Mastodon, and because that instance was the one everyone was suggesting for KBin at the time. I’ll most likely spin up my own instance for myself and maybe a small group of others to join.
In my experience, with both coding and natural sciences, a slightly incorrect answer that you attempt to apply, realize is wrong in some way during initial testing/analysis, then you tweak until it’s correct, is very useful, especially compared to not receiving any answer or being ridiculed by internet randos.