Syzygium jambos ?
I want to say that too, but I feel like with more research I did before there was a different species name... when searching
https://toptropicals.com/html/toptropicals/plant_wk/rose_apple.htmYou also pull up pictures of 'Red' Rose apples which are a different species, even the flowers are different color.
Plus even toptropicals has the wrong Thai name as well, it may be Called 'Chompuu' but only with addendum "nam dog mai" (like the famous mango) Chompuu Nam Dog Mai.
Chompuu = can refer to Psidium and Syzygium species in Thai
Nam Dog Mai = nectar