Sorry if I don't belong answering this, but I wore bras for fifteen years and now I have a teenaged daughter going through this.
I have never heard any medical professional say anything about underwire, and I think most relevant information about it is going to come from individual consumers and maybe from the fashion industry. I always associated underwire with middle-aged and older women, and women with lots of kids. I used bras with it sometimes, as it can help keep a lovely shape and prevent uniboob, but bras with underwire fall apart more quickly, and when they poke through it can be painful.
If you can find a bra with plastic "underwire" it might be a nice compromise. I do know cisgirls who swear up and down that their boob symmetry and tightness comes from sleeping in a tight bra, but I have no way of checking on that, obviously.