Can they approve accepting payments in an application like Vkontakte?

Question

In-app purchases

Hi all.
Friends ask me to make a mobile application and a website so that they can sell digital content, such as author's music, remixes, etc.
In general, the question is whether Google and the appstore will miss applications that use in-app payments through third-party processing, such as payonline or Ya.Kassa, or CloudPayments (I like it the most). Naturally, this application will have a player so that you can listen to music inside the application.
But there will also be a web version of this application, such as a website. Where you can also buy music.
Looked at Vkontakte.
They sell stickers on their mobile apps, but! The processing is not used by Google, I don’t know how it is on the iPhone, it’s not at hand right now.
That's actually the question arose.
Guys, if I'm wrong, please correct me. I understand, I’m sitting in this topic, this nuance does not give rest, and the percentage of Google with Apple is normal, I would like to get around this somehow, if possible.