A normal strapless bra should be fine, I agree you don't really need a maternity specific one. May need to remeasure and get a different size than usual
They advise to avoid underwire styles when pregnant but you can get regular bras for now. I’ve got a few cheap underwire ones. You’ll probably find you’ve gone up one or two chest width sizes already. Cup size may not be too different yet. Get measured for maternity bras 3rd trimester as close to the birth as you can. They always leave a bit of room on the cup for the milk to come in. They then recommend another bra for a few months in when the milks called down a bit. X
I don't think I've ever seen a strapless maternity bra. For my wedding day, I just wore a normal strapless bra and managed to feed my toddler by just lowering the cup if it makes sense. I'm assuming you're worried about breastfeeding. Otherwise you don't really need a maternity bra anyway! Xx