Rosemary in a pot needs outdoor sun - at least for part of the day; and it needs regular water - but not so much that it is soaking wet and so needs good drainage; it also will need weak fertilizer once a month.

I have a now huge Rosemary in a huge pot by the front door that people love to touch as they come and go from my home; it has been there 4 years now and doing great.

Rosemary is a Mediterranean species... it's fine in full sun & heat but it won't tolerate staying damp. High humidity makes it very hard to dry out sufficiently between waterings... more especially when you upsize the pot.

you don't specify where in MY you are but if it's like KL where it rains daily during monsoon... I'd plant it like a cactus and give it really sandy non-water-retaining mix... even a potful of just coarse sand or brick crumbs is better than any damp soil/peaty mix. Let the mix dry out before watering again.

The tropical humidity & dampness is really tough on these plants... there's very little window between "nicely dry" (can wait till tomorrow to water) and "too dry" (you should've watered me yesterday!) as Rosemary don't store water like succulents. And Rosemary leaves don't wilt as prewarning, they just go brown at tips scarily quickly once too dry.

Why don't you plant it in the ground? I have sandy soil and it loves being in the ground. I rarely water or feed it and it still looks great.