Two reasons I sold all 16 units - How can I avoid a repeat?

[Jay Abdallah]

Since 2016, I bought (with the intention of keeping) 16 doors in Buffalo, NY.  I live in a foreign country, and depended on a property manager to manage my portfolio.  After 5 years of abuse, miscalculations, grossly inaccurate estimates, and almost zero cash flow, I decided to sell everything.  Due to appreciation, I made out OK.  Now I'm looking to get back into real estate, but how do I avoid these two pitfalls?

1. Property managers that swallow up all free cash flow with their management, finders, and project management fees
2. Contractors (also overseen by property manager) that charge obscene fees for simple tasks
 
Of course, COVID and NY State's eviction moratorium didn't help.  I still shouldn't have cash flowed as low as I did, especially since most of my properties were bought and renovated in cash. 

THANK YOU