have you read the Webtoon SAVE ME then? BigHit collaborated with the comic company LICO to publish it on webtoon. I'd suggest reading it if you're interested in the BU. also, check out xCeleste's (on youtube) summary of the BU (again if you're interested)
It's really confusing for me personally, still trying to learn it though.
also have you seen the WINGS short films they're kinda scary in a creepy way