@Vasilii Baban
I am about to buy a duplex myself and house hack.
I am having the same issue as you in terms of the numbers not cash flowing.
I came up with a couple of ideas to increase cash flow that help my numbers improve.
I am only looking at duplexes that have parking (not all the duplexes in my area have parking). This way I can charge for the parking spots if the tenants want them.
I am also planning on renting space in the cellar for storage. I will assemble cages that the tenants can put locks on if they would like to pay for additional storage. You could tactfully find out if your potential tenants have cars when interviewing them.
Also if the 2nd unit is not submetered I will install submetering equipment so that I can split at least the electrical portion of the utilities. I am an electrician and can set this up myself. But it is not that expensive to do.
I am also leaning towards conventional financing so that the initial fees are lower and I can buy my way out of the mortgage insurance if any capital comes my way.
The PMI dropping off after a year (if I can make that happen) would improve the numbers.