The question is dramatizing things a bit - by 2026, COVID has long since become just another common respiratory illness that goes around everywhere, including your hometown. Tourists are still traveling to Phuket just as much as before, and nobody's canceling trips en masse.
If you're not in a risk group (elderly, serious health issues), there's really nothing to worry about. Yeah, you might catch something - just like you could at home or anywhere else where people gather. But that's not a reason to change your plans. In October-November it's peak season there, the weather's great, hotels are packed with tourists - people are eating, swimming, walking around without any fear.
Just use common sense: if you're feeling under the weather before your flight, stay home; wear a mask if you want to (on the plane, in crowded places), but nobody's going to force you. Otherwise, plan your vacation the way you were planning it.