I would never want that many units. I have 2 units now, and would maybe.. MAYBE go to 10 units. But anything after that, it becomes a full time job and you're wearing a lot of different hats.
I do like it though. The key is that when you land a good tenant, you keep them, whatever the cost. If that means keeping rents 20-25% lower than FMV, so be it. It's worth losing a few hundred a month to have tenants who don't damage a place, and ultimately leave after a year or two anyways, leaving you a gap in rent payments that would likely offset whatever you made by charging more rent.
I really recommend this side gig, especially with wages generally just not keeping up. I make an extra $30k/year, get a HECK of a lot of write-offs. Still have to pay high NY taxes, but the 2nd mortgage is basically just a forced savings account.