How to find funding for unconventional renovation to add units to my mixed use home

[Alex Padilla]

I have a mixed use property with 2 units (main home and ADU) where the town has approved an additional 3 units because it's mixed use zoning. I'm estimating the cost will be about 350k since it will be a conversion and there won't be a need to construct anything from the ground up. Here's my dilemma.

I have the cash to make the conversion, but ideally I'd like to finance ~80% of the cost. The problem is I got the property at 3.5% @ 800k & any kind of financing will require me to refinance so the home can go as collateral if anything goes sideways. Makes sense, no problem, but I'm not doing that given interest is at 7% now. So my question is, does anyone know of any hard money lender or other unconventional way to get this money for the units based on purely on future cash flow?