Yup... At this point I have to agree. You have to get Antigen test to get into USA anways.
Worth it for us Canadians to pay extra to get PCR test instead and having peace of mind, being covered for both USA and connecting onto Peru/Panama. The 72 hour limit should cover the 24 hours it takes to get results for the test and get to final destination from Canada->USA->South America; even with an overnight in US.