We spent a week on the island in early September last year. While many of the top restaurants on the island were closed, both with a mix of seasonal closures and others choosing to shutter for the remainder of what was a very weak summer due to COVID, we still had a lovely time. If I remember correctly, we really had a small handful of restaurants to choose from, but the trade off were beaches that were truly empty every day. We were often the only people on every beach we went to.
I think we rotated between La Crepêrie, Le Repaire, Zion, Bagatelle, Bar de L'Oubli, and perhaps one or two other places that were open. Very slim pickings, but you have to really go out of your way to have a bad meal on the island. And, given the travel environment last September, I was truly fortunate to be able to get down to the island, enjoy some wonderful days on the beach and great meals outdoors, and escape working from home 24/7.
The only thing to keep in mind is the elevated hurricane risk. Bit of a roll of the dice, but we lucked out and didn't have any storms last year.