In the past, they sometimes UG for free or call to offer an upsell or paid UG.
If you have your record marked, no upgrade, then they won’t call.
Since the restart, due to ships not being full, they have done some paid upgrades
at Guest services. Go as soon as you board and ask, it doesn’t hurt. Then, if they say that they will get back to you, go enjoy lunch and see what happens. Many have reported decent deals, so I’d go for it.
I would look at what is open and have an idea what cabins that I was interested in before the sailing.
Good luck!