I try to avoid the cattle boats.
I wouldn't say any were cattle boats, but the closest was the one out of Fajardo -- about 20 divers on that boat when we went in Feb 2021.
Try the west and south coasts. I don't think cattle boats are possible over there, they don't have any decent harbors, so the boats are very small. Two we used in Feb 2021:
Taino Divers - Rincon - Boat probably had room for 10 to 12 divers, but when we went it was my wife and I, plus one other family of 4 (mom, dad, two kids) and 2 crew. No real harbor or pier so everyone helps load the boat (fire line style) while it rests on/near the beach, then climb aboard with a ladder. It was fun. We didn't get to go to the island, conditions did not allow (and it was choppy, not just an excuse), but "Horseshoe Reef" and the other dive site were very nice -- the 2nd site I found myself at 82' depth and could still see the boat at the surface, that was a first for me (at home it gets dark in 20' of water).
Paradise Scuba - La Parguera - This was the smallest boat. My wife and I were the only paid divers, but the crew was 4 -- with the six of us, the boat was full, but of course the crew let us sit in comfort and didn't feel cramped. The have a dock, and from their pictures on Google Maps they have a larger boat also, but still not the size of the boat out of Fajardo that goes to the eastern islands (need a big boat to go there). We went to "The Aquariam" and one other spot, both dives were great, at least similar to other dives in PR (20-30' viz).
It may be hard to get a boat to one of the western, northern or southern islands this time of year -- we couldn't last Feb. The boat out of Fajardo (can't remember the name) was larger, and more like a party boat (cattle boat?) with snorkelers and divers, people puking in buckets, and one DM inviting all the young girls to his "private island" after the trip was over... I would still do it again though, the viz off Culebra was 50'+ and amazing, lots of life and healthy coral. I guess before trying that boat again, I might fly to the island and dive from shore instead -- although I'd be worried about currents and no boat to come find me, for you, with your experience, that might not be a problem.
