The picture I use for professional stuff is a shoulder up photo of me in front of a brick wall with some greenery in front of it. I'm wearing a black hat, plain shirt, glasses, and a backpack. I've gotten dozens of interviews and recently a new job with this photo that I've used since 2020. I've even received compliments on it being a, "not fake photo".

Being too much of a "suit" in the developer world can actually harm your chances IMO. Meta actively tells interview participants to come as they are and outright says to not wear a tie because in their own words, "we care about your abilities, not your clothes". Obviously clean up and look nice, but that doesn't mean you gotta stress about appearance. I've personally done all my interviews in various hoodies and it's never been an issue or counted against me as far as I can tell.

Obviously fintech and finance is gonna be a little more formal, but I don't personally want to work somewhere where how people dress is anyone's concern.