I am in a building built in 1932, on the top floor. My shower drain gets blocked intermittently. I have been told by the strata plumber that the issue is with the pipe which is degrading and needs replacement – to do that we are going to have to rip the entire bathroom out. So there may be a similar issue with your plumbing. And yes, a lot of hair goes down that drain.
I suggest you get the strata plumber out to investigate so you have a clear picture of all the issues and who is responsible for what.