Musi does work well for playing music in the background on iOS.

A downside to Musi is that after playing a video a full screen ad will often pop up in a way that feels invasive and can be difficult to avoid inadvertently clicking. The behavior feels like malware, which leaves me concerned that the developers behind the app might hold flexible ethics and engage in practices such as covertly monetizing user data.

I'm not sure that Apple would ban it. Do they really care if people bypass YouTube's intended restrictions? Obviously Google cares, so you won't be seeing NewPipe on the Play Store.

> #5 in Music > Stream any song from YouTube

Wow and it's been up for years! Do they scrape YouTube like NewPipe? How come Google didn't go nuts about taking it down?