Too bad banks are so in love with their inflexible little tick boxes. We just didn't fit into them.
Weren't you around during the finacial meltdown in 2008? There is a reason they have all those little tick boxes. Loan volume is what keeps mortgage rates low. For loan volume they need to have a simple, no thought, no work cookie cutter approval method.
Your job, if you want one of those loans, is to shuffle your finances around so that you fit in the little boxes. Which means you need to show an income stream that looks & behaves very much like a steady paycheck -- coming from a well-known institution. Which means a broker who you have instructed to send you $X a month, and you can show those deposits hitting your checking account for 2 or 3 months.
Yu can either go with the flow and get the mortgage, or you can rail at the lenders and get turned down.