So I just wanna ask something about that

If I make an edit and upload it to musical.ly, is that personal use? Because I don‘t make money out of it?

you're getting likes/thumbs up/fans and views, which are all payments in a way, so it's commercial use. Personal use is writing your grandma a letter with a font. But if she likes it and becomes a hardcore fan, then it's commercial...

nah just personal use