Yup, Nezchan beat me to it. A lot of AAVE phrases/vocab have made their way into more mainstream usage without people realizing the origin (i.e. stuff like "throwing shade"/"slay"/"____ gives me life"), and based on where I have seen "you do you" used I kind of assumed it fell into the same category. But who knows, it's basically impossible to google (all I got was some asinine article about millenials) and it's not like anyone officially tracks this type of thing ¯_(ツ)_/¯ Anyways, going back to the original point, if this is the case, then English speakers from outside the US might find that phrase unclear/confusing, which is too bad since the meaning seems to fit quite nicely. As for whether translations should avoid phrases that are specific to American English, that's a different issue.
...it seems I keep inadvertently derailing this thread from being about FF so I'll shut up now!
SPOILER ALERT!! Enah was actually Sung-pyo in a mask the whole time :O
AAVE is actually more encompassing than just phrases or vocabulary. It specifically speaks to how black people merged English with native languages spoken in parts of West Africa (its actually a mix of more than just that, but that's the basic gist of it).
Two of the most distinctive features of AAVE is the use of tense ("I been at the river" versus "I went down to the river") and double negatives ("I aint seen him nowhere" verses "I haven't seen him at all"). Most black people in the U.S. are considered to be bi-dialectical as they can speak AAVE and Standard American English (aka "The Queen's English").
Wikipedia actually has a really great article if you are interested in learning more: https://en.wikipedia.org/wiki/African_American_Vernacular_English
Most of the phraseology used today that is attributed to AAVE actually comes from black and latino LGBTQ communities and was basically co-opted (specifically terms such as "bitch read" "shade tree" "throwing shade" "everlasting life" etc). I won't get into how and why (because who really wants to have a discussion about race, gender, queerness, and money: not me), but I think you get my point.
Oh and as always thanks halmoni for the translation.
Halmoni is doing halmoni. That's how you do you, boo boo.