Phuket Island, beaches and activities, Thailand ✈️

I travel to Thailand often and you people are such a huge help. So thanks for that!

I’ll have a few spare days before and after a liveaboard dive trip to the Similan Islands and I’d like to make the most of them. I’m into nature, beaches, hiking and good, authentic food. I’m less about nightlife or bar scenes. What area should I stay? I’d love a boutique style hotel (rather than a monster resort mini city) or private room in a hostel. If it’s in the jungle, even better! Should I make the trek down to Phuket city? Most of what I read about it sounds like a loud, polluted party. Khao Lak seems like a slower pace. Is it a nice jumping off point for jungle excursions/hikes?

Any help is greatly appreciated!