i don't want my songs to be taken down for reasons like the whole george harrison my sweet lord/he's so fine thing.
using existing chord progressions is both legal and normal. it's like having 4 wheels on a car. Admittedly there have been some strange court cases out there, but the real factor here is not the chords, it's whether or not your song becomes extremely popular and catches the attention of someone with a lot of courtroom talent. If you never use existing chord sequences you're probably going to have a pretty bad time in the long term