Most of my experience in Cozumel (300 or so dives) has been mostly with Dressel. I like the short boat rides, relatively festive and less experienced diver base. It makes it fun.
I really like Iberostar. The food is good (and keeps improving it seems every time I go) and I like the vibe. My biggest complaint is the small rooms.
I'm headed out there in a few weeks, and chose not to dive with Dressel mostly due to distancing concerns. I'm working with a private operator with daily private trips for me and my dive group. But I did inquire about what they currently have to offer, i'll post here:
They do two tank dives every morning. Afternoon two tank dives are currently on Tuesday, Thursday, and Saturday just to P. Gardens and C. Shallows. I see no reference to nite dives at this time.
If you book 10 two tank dives (they can be split) it works out to be $33.60 per dive with Nitrox.
Historicaly speaking, the morning dives are limited to 60 minutes each and the afternoon dives are limited to 50 minutes. Max depth is 100 feet and you are to stay with your assigned guide.