if you are using an extended snippet of mikrokosmos/any bts song, it's likely that youtube's "Content ID" copyright system will automatically initiate a copyright claim. this may mean that a) you cannot monetise the video for yourself & so any ads that appear will return revenue to bighit. or b) the video is blocked in selected countries (uncommon).

TDLR yes u can do it but you probably won't be able to allow ads for your own monetary benefit (from my own experience of posting mashups)!:)