2021 Best place to invest in STR

I think you have a fundamental misunderstanding of Cap Rate? Cap rate can be calculated on a single family rental home just the same as any other rental producing property. Cap Rate excludes out any consideration of financing or the costs of obtaining financing (among other things). I'm not disagreeing with you if you are implying that COC return is a better way of evaluating a short term rental, but to simply say you can't do cap rate on a single family rental home is false.