I think most libertarian socialists would agree that volunteer cooperation (contracting, trade, want to rent a room, etc) is fine. It’s just about not reinforcing hierarchy the way other systems do. If there are functions needed to maintain that hierarchy (police, the state, etc), it wasn’t free to begin with. I think we agree here
Discussion
If voluntary contracting and trade are fine, then we do agree—you're describing anarcho-capitalism. But most libertarian socialist and collectivist frameworks are obsessed with regulating economic arrangements and telling people what they can't do, even voluntarily... or at least that's my understanding.
If it's just about encouraging people in a certain direction without enforcement, then it's just an extension of ancap with different preferences. If not - what's the actual difference?