It is not about making as much profit as possible, but a fair return on your money.
If I had mortgages (and did in the past) I still used a 10% Return on Investment as a fair profit. 7% return on the money (as I can easily get in securities and 3% for my time and effort (management).
If I paid professional managers, those costs would be figured in the expenses before setting rents to give a fair profit.
There is an old axiom in investing: bears make money, bulls make money, pigs get slaughtered. Don’t be greedy! Make the rents too high and tenants can’t pay, or double up causing excess wear and tear. Real Estate is not a get rich quick scheme. It is hard work over the long term.