Honestly this reads like a Playa Mujeres wishlist. Quiet, low stress, lots of space, and way less of the chair saving chaos you see in the hotel zone. For pure lounging and switching your brain off, that area is hard to beat.
Beloved is the most relaxed of the three. Smaller, very calm, and service focused. It can feel almost sleepy, which sounds like a plus in your case. Excellence is a bit bigger and busier, but Club level helps a lot with reserved spaces and better service. Atelier Inspira is beautiful and more modern, but it feels slightly more energetic than the other two.
None of these are heavy on timeshare pressure, especially compared to other Cancun resorts. Chair competition is minimal if you’re not showing up at noon. Cabanas are available, usually for a fee, and shade is much easier to find than in most places.
With your budget and priorities, Beloved or Excellence Club feel like the safest bets. If the goal is maximum chill and minimum decisions, Beloved is probably the winner.