A better solution would be an entirely community driven app store that is not beholden to any corporate influence.
FDroid exists already. Okay, it doesn't host proprietary apps, but whatever. The point is, this isn't a tech problem anymore, it's not a problem where someone can just make a new platform to solve everything. Google has contracts with phone manufacturers that ban them from adding 3rd-party app stores alongside Google Play. And none of these app stores are going to show up on iOS. It's a cultural/legal problem at this…
That's kinda like Microsoft requiring a payment for every PC sold whether their OS was installed or not. Predatory contracts from a monopolistic company... who would have thought.