Welcome. 20/20 hindsight from 30 years later, divorce from my first wife was one of the best things that ever happened to me. It was also yucky at the time but no longer.
And yes absolutely sailing on a Sunfish counts. Probably the best experience you can have for proper sail trim and handling. On a small boat you get instant results from whatever you do with the sails
so you can see what happens when you pull this line or that. Bigger boats the results are much more subtle.
The big difference is the maintenance
, systems, etc. but that is something easily learned with time and practice.
From your handle I guess you are a diver? Taking your own boat is the best way to go.
I am also impressed that someone 71 years old is making such a commitment to sailing.