If you’re paying the same amount monthly, your cash flow is the same. Are we not comparing apples to apples here? I mean a traditional fixed mortgage.

I’m comparing a mortgage with a high rate and lower principal to one with a lower rate and high principal, where the minimum monthly payments are the same and the owner pays the minimum.

A high interest mortgage just means that you pay more total interest over the life of the mortgage. In any case traditional mortgages are front-loaded, so you pay more towards interest up front than you do principal.