While alternative app stores operate independently and are required by EU law, Apple is still in a position to exert some control. This became apparent a few weeks ago, when iTorrent users suddenly ran into trouble when installing the app.
Thought this was an interesting story, since it’s pretty analagous to the recent Android situation, with third party app stores being enabled to some extent, but the company retaining ultimate censorship power.
I feel like you’re just being obtuse on purpose. There are many people, myself included, who would use a Linux phone if the OS was there and you could get one with flagship specs. As it stands, you cannot.