Tenants don't normalyl put up a big fight, physical or legal.  

Can't fight city hall, right!

I tried to reason with them but they refused to pay the rent, to kick out the extra people, and also refused to leave the apartment.The tenants started to have fights which damaged the property, parties, smoking marijuana inside the home and in front of the house, and getting into altercations with my neighbors.

Still fighting- Certainly less 2020 did not help us.

And if they can’t reduce your taxes, they don’t charge you anything but will still fight for you.

Even if you find a decently priced property, you're going to be fighting for it with numerous other investors. 

As Harrison mentioned, multi-family supply is slim and when they pop up it's a dog fight, but if you're hungry enough and persistent enough, you'll land one. 

There are more and more investors/syndicators fighting over the same deals. 

I should be grandfathered in until I decide to sell the property, not when the lease expires.Should I try and fight this or is this a lost cause?  

Early on there was a murder and a gang fight.