Want to downsize but renewal coming up

My renewal is in March 2026. I'm not feeling very safe in my current workplace with AI coming and in addition I have a chronic health condition. Not sure how much longer I physically can work. Not great credit, single mom, with a B lender, $70k income. I do not want to leave my neighborhood due to the children and their school.

Current home value at $1.3m, 5 bedroom double car home. Mortgage and debt totals $450k. Want to downsize to a $1m single car home on a smaller lot as current house is too much work with my health conditions. I will still need a mortgage. Would like to list for the Spring.

My mortgage broker did not seem confident that a B lender would offer me a portable mortgage. How common is it for B lenders to do a portable mortgage, with my equity and mortgage needs?