When you say you have body jewellery that you won't negotiate on and how covering your tattoos is compromising your identity then it does sound like it's a fairly big concern, especially if you plan on ruling out places to work based on whether they'll let you have piercings and tattoos on show.
To put that into persepctive, that would rule out every secondary school in my LA and the neighbouring LA plus most other secondaries in my county.
I interview for teacher training and it is noted when people turn up not dressed professionally for school. When we discuss applications we make a note of things to be raised/reminded of later if they get a place. Dress code, tattoos and piercings are a day 1 of training reminder of professional expectations.
Anyone who is put off teaching because they have to follow a fairly simple dress code probably doesn't have the resilience to manage a career in teaching. If someone's commitment to a career are so flimsy that they would walk away over a dress code then when things actually get difficult I can't see them lasting.
it's probably representative of deeper issues within teaching
It's a dress code. There are many issues in teaching. Expecting staff to dress professionally isn't one of them
Esspecially if teachers are afraid to challenge the status quo and support fellow teachers
Teachers aren't afraid to challenge the status quo. We just know what to challenge and how/where to challenge. My 'things I care about in school amd would like to change' list has quite a few things on it. Dress code wouldn't be on it because it's a non issue.
I'm a career changer to teaching too so please take this as intended, as a career changer it can be tempting to go into teaching thinking 'but in my last line of work... i never had to do.. x y z is pointless because in my last job we...' There's huge benefits of having a career before teaching, but remember that you are just as new to the field as anyone else on your course and there's lots to learn. Deciding before starting that things are pointless and x y z are probably reasons people don't stay in a profession that you're not part of yet could (if expressed badly in schools) easily rub colleagues up the wrong way.