Compare the fixed term before comparing the lender
A fixed rate is a category, not a single mortgage. One-, three-, and five-year terms can price differently because the bond-market cost and lender strategy differ by term. Start with the period you can realistically keep, then compare lenders inside that term.
If a move, sale, renovation, business change, or refinance is plausible before maturity, a slightly higher rate on a shorter or more portable mortgage can cost less than breaking the lowest five-year offer early.