We are traveling for the first time to Breathless in December, but have done TTR (x2) & Desire in the past. After doing quite a bit of research it sounds like Breathless used to allow topless in/around the pool, but pulled that back within the last few years. I haven't heard that the Secret side allows topless, but that would be outstanding. From my understanding, it's totally fine to go topless at the beach. If anyone gives a hard time, Desire is right next door and you can be fully naked on the beach there (we will!) without anyone giving it a second thought.
We visited Breathless in 2019 and even then, topless was very restricted (party pool area only and only when sunbathing). As for Desire access, unless it has changed, there was no easy way to access Desires beach from Breathless due to the sea wall