Can you strike a Youtuber?

I want to strike someone on YouTube (don't ask if this is about, it's about private reasons)

He is a Fortnite Youtuber with around 50,000 subscribers and has around 200 viewers per stream (are still personal problems)

Could I now join his lobby and play copyright music and thereby strike the stream? Or does nothing happen there because it is smaller?

Music is generally allowed during a stream, but you can get strikes if you can watch the stream afterwards.