Strict?!? Lol I worked for 6 years. When I first started it was button downs or pollos and almost dress pants we wouldn’t even wear jeans. No facial piercings and no un natural hair colors lol they have REALLY EASED UP IM SO GRATEFUL.

Black tees/button downs and skinny black zippery pants can look pretty alt when you've got fun hair/the general vibe down. I wouldn't wear docs to work because I wouldn't want to pour boiled milk on hundred dollar shoes, but unless your store is stricter than mine they wouldn't violate anything.

I mostly wear black or grey tees or grey plaid flannels (they are allowed as long as they colors are muted) and black jeans. As for shoes, I have a pair of nonslip kitchen shoes but Docs are fine. Be prepared to get them covered in coffee, milk, syrup and mocha powder though.

I do a lot of black and white stripe shirts. Makes me feel like Gerard Way

I have my philtrum pierced, and thats allowed as long as its not bigger than a dime I believe. For the most part, as far as actual clothes go, I just wear all black shirt (black tshirts are fine now) and pants and in-code boots.
I PERSONALLY dont want my more expensive or favorite clothes getting ruined with milk and syrup anyway tbh, so I definitely do suggest toning way down in the clothing department if youre looking to not stain things that are stainable. Youre gonna shake a coconut milk or explode a whipped cream on you one day or get mocha or frap roast splattered up your sleeves.
If youre still needing a little more self expression, try playing around with haircut/style or asking your SM about what pins are allowed on your hat/apron (not sure if everywhere is as anal about pins as my current store, bc past stores I've worked at have been really chill about pins)

So we can have unnatural hair?