My whole team and I work remotely, so it’s not the exact same situation as you, but I made a concerted effort from day one to set social boundaries with my colleagues. First week on the job my manager found out I’m single and offered to set me up with people. I acted very weird about it, purposefully exaggerating how uncomfortable the offer made me, and she got the hint. We have a very friendly and cordial working relationship, but she no longer pries into my personal life unless I volunteer information. Been happily working under her for four years now.
That work/life separation quickly filtered down to the rest of my colleagues, to the point where now they act a little weird when a company call starts to get personal. Mission accomplished.
I think the key thing is that you’ll never get through to people if they can’t read social cues. Sounds like your workplace cliques are filled with those types of oblivious folks, so you might just need to be completely explicit about keeping things fully professional. I’m lucky that my manager is emotionally intelligent, but that’s pretty rare these days.