House hacking to STR

[Beyonce Davis]

The first home I bought was with my brother , I helped with the downpayment and he covers the mortgage payment as rent. We are both on the title and the loan but since he covers the payment I have had some lenders exclude this one house but there was one that refused to. 
I have been following a process where I buy a home and live in it for a year then convert to STR and I have acquired 3 homes this way. So technically I have 4 mortgages in my name. In the last 4 years, now I'm facing some roadblock acquiring more. How have anyone else handles this obstacle without high interest, high down payment DSCR loan.