Well, this was quite the **** storm, but it's over. Thanks for your comments. If your oncologist believes that you are immunocompromised, of course you should wait for a covid vaccine. It might come out a lot sooner than next summer, and you would be a priority candidate. Vaccine options are already being mass produced in anticipation of successful phase 3 trials. For you, vacationing in winter before a covid vaccine makes as little sense as vacationing in winter without a flu shot.
Directly on-topic, I've crossed out dive-ops that will not handle the majority of my gear, even though I'll be renting a car and can ferry the stuff back and forth. It's a huge pain to clean everything daily. I hadn't thought to ask about this before reading this thread.
I am probably OK to travel but she cares about me.She’s great at suggesting without directing. Our plan is cenotes and Coz in May!
Take care.