One decided to break lease due to job loss, and we worked with them to move out and re-lease asap so an eviction and additional charges were not placed on their record.I feel for those that are dealing with tenants playing the system.

However, if you were looking for lower turnover and more of an appreciation play vs. cash flow single family could still be a good strategy, all depends on your goals as others have mentioned previously.

Short term: (1) determine investment goals (target ROI, markets, property size, capital stack); use this to dictate where and with whom we invest. (2) market research to evaluate where and what will meet investment goals (this is where my OP question about analyzing properties with rent control comes into play). (3) decide to sell or refi our 4-unit property in line with points (1) and (2). (4) analyze cost benefit of selling GP interest as capital source in line with points (1) and (2).

Your DTI does come in to play, but you have to take what you can get! 

It's been a great equity play (estimate appreciation at 70%) but from a cash flow perspective I am only about $75 net positive each month. 

The tenant who signed up for the new internet service in his name also never responds when I try to communicate and he has disturbed the other tenant several times by playing games late at night and being loud (the lease also states no one should cause disturbances and tenants areentitled to quiet enjoyment of the premises).My question is: what action should I take here?

Apart from my personal mistake, was there something larger at play that caused this to happen?

A little background to myself:- I am in my last year of school- I am an Apprentice Plumber (Commercial)- I work on some things to do with E-Commerce and Stocks/Crypto- I love playing sports and going to the gymMy main goal for my life is to have financial freedom as we most do but for me travelling and experiencing the wonders this world has to offer really drives me.

There are many variables at play.

You can't win if you don't play the game.