Looking for advice on where to stay for an anniversary trip

I’m looking to book a trip with my wife next year and trying to decide the best place to go.

Here’s some info about the « plan » if you can call it one:

• Logistics:
  • Target dates are October 15-20
  • Flying in from the mid-Atlantic, most likely via MIA, on American Airlines
  • Looking for Marriott properties under 400,000 points
  • Just us! Kids are staying home
• What we’d want to do:
  • Primarily relax on the beach
  • Eat mostly on property but get out to have a meal once or twice
  • Maybe do some excursions like snorkeling, horseback riding, or fishing, but nothing too intense and definitely not all-day stuff
  • We’re not into places that are jam packed with people or with constant things going on.
  • We’re « take it or leave it » on all-inclusive. We did it once before and felt like we had to overindulge to get our money’s worth, so it isn’t something we’d seek out again.

Contenders right now:

1. Westin Grand Cayman – looks like a great property on an island with plenty to do if we want
2. French Leave Resort, Bahamas – looks awesome to have a villa to ourselves, but needing to take a vehicle to the beach doesn’t sound like something we’d love
3. Ritz-Carlton, Aruba – beautiful beach and we’ve been to Aruba (our only Caribbean destination!)
4. St. Kitts Marriott Resort & Casino – looks lovely but I’m almost put off by how inexpensive it is (128,000 points for a 5-night stay). What’s wrong with this place to be so cheap?
5. Royalton Grenada – pictures look good but reviews not so much

I don’t really know all that much about island destinations. Any tips or advice are appreciated!