Wow, that certainly is a complicated flight schedule! You are much braver than I would be, booking that!!

Are you vaccinated and boosted? Because if you're only vaccinated, and not boosted, for sure you would need to test, to enter SXM. I can't tell what the total time period that we are talking about here is, as to whether it is possible for you to get a PCR test, one day before entry into the US, and the same test would be within less than 48 hours from when you are due to leave on your flight to SXM from Miami? For entry into SXM, you can do a PCR test 48 hours out. If it were ME, I might plan on trying to do the PCR test, if the timing would work for you. If you don't get an answer to your email, you might try to call also.