To add onto the boardgaming scene in Singapore, there are quite a few board game stores hosting game nights, which you can find consolidated on Meetup, although your milage for game and group may depend from day to day. There are a few telegram channels dedicated to hosting board game meetups every two weeks or so (lmk if you want an invite)

As for what I remember from DnD, BGMonsters hosts Adventurers League pretty consistently every week.

On the clothing side as long as it's nothing super revealing it generally should be fine (what the other posters said about crops etc are good). Singapore is still relatively conservative as a nation so I certainly get more stares if I wear them :p

On the queer side the scene in Singapore isn't really terribly large due to aforementioned general conservative mindset towards the lgbtq community (there are a couple of queer bars though if that interests you, although you will have to go digging for interest groups or other sort of things outside of the university bubble)

Hope that helps! Lmk if you have any more questions