I was at both properties in the past month. Stayed 15 wonderful nights at the St. Regis. And had a planned 4 night stay cut short at the Ritz to 2 nights due to service related issues.

You can't go wrong with the STR. However, the Ritz is a wonderful property but it will need some time until they are up to the Ritz standards.

if you're planning to go mid next year, I say that could be ok at the Ritz as their property is much nicer than the STR. But we had a wonderful stay at the STR (keep in mind this was our 3rd visit to the STR) and you can't go wrong with the service.

And no, the Ritz doesn't require another PCR unless you were staying at another property pre-Ritz (that is the case for all resorts in the Maldives).