I love the idea of a bedroom/ beauty room!! Beyond!! I see your struggle in a room without natural light … but luckily, that is a super simple thing to fix!!
Get creative with hanging lights, maybe some light cord kits? (This one or this one are cute!) Then create yourself a traditional vanity set up with a desk, and vanity light mirror, so you have light coming from different angles! A good way to style would be with a pendant light hanging from the ceiling on either side of the mirror, getting balance and symmetry in there, too!
If you don’t want to or can’t hang lights, sconces will work, too! Think like the ones we installed for Joslyn’s place!!