Yale is one/the leading places for long Covid research.
One of their trials, (note) in a different context where people already have long covid, will use the Paxlovid protocol linked below, even longer than the 7-10 days I mentioned above.
Personally I’d see if any creative possibilities to get another 2-5 extra days supply (pending your individual profile, liver health, etc of course). (It’s not the standard in the US either but I know several people who did it that way).