Earlier quoted context omitted.
Beat Saber and Meta aren't responsible for that. You won't get sued for that just like singing Taylor Swift in the shower is permissible.
I mean they are. They allow hundreds of thousands of players to sideload a modded APK in using their developer mode. This is detectable but they tacitly allow it because it sells a lot of copies of the game and the headset. And I am thankful they do!
There's zero liability for Beat Saber or Meta here. People distributing the pirated music would be liable.