@Whatif WEll, there are two things to consider when picking a server.
1) the topic and how much it is enforced, if any,
2) The moderation policy
QOTO for example is a STEM instance but we dont enforce the subject at all, it just means most of our users are into STEM as a profession or student.
As for our moderation policy, generally we just ask people to be respectful to eachother and not to harass each other. The idea of mutual respect seems to work for the most part.