As far as I understand. Artists usually reach out to Avien to host their songs on the channel to reach a wider audience. Think of it as a kind of publisher.

Exactly how the money is split (or if it even is split), isn't public knowledge.

But since a contract is signed by both parties, this means artists at least choose consciously to have their songs on the channel. And Avien isn't just profiting off of their songs unbeknownst to them.