Joining Amazon KDP Select

Salam!

My question is about selling e-books on kindle. Is it halal to join what they call KDP select? People pay a monthly subscription fee and can read how many books they want. But my confusion comes from where the royalties come from: “Inclusion in the Kindle Unlimited program with possibility to earn a share of the KDP Select Global Fund”.

JazakAllah khair.

Wasalam

May Allah bless you.

My understanding is that you are paid according to the number of pages red by the customers. There is fixed percentage allocated for the author minus any Amazon cost.
I don’t see any issues with such arrangement unless more information come to light and prove otherwise.

And Allah knows best!