I completely understand the constant fear of eating the wrong thing and hurting the baby, I was the same! Fresh mangosteen is mostly fine in small quantities, but if it makes you anxious, just skip it. Your peace of mind is much more important than trying a new fruit right now.
Honestly, we don't need to overcomplicate things with exotic fruits if we're unsure. If you really want to eat mangus fruit, just have one or two pieces occasionally. But if it's expensive or hard to find fresh, normal local fruits like apples and bananas are just as great and much safer.
Oh, the pregnancy cravings are so real, even for random fruits like mangus! Yes, you can eat it in moderation, just don't go eating a whole basket at once. Honestly, at this point in my third trimester, I'm just happy if anything stays down, haha!
Mangosteen is packed with antioxidants and folate, so eating the fresh fruit in moderate amounts is generally safe. However, please avoid any mangosteen herbal supplements as they aren't regulated. It is always wise to double-check with your gynac before adding new exotic fruits to your diet.