This sounds reasonable but when you start doing the math it just doesn't make sense. Creating the device and getting it certified world wide is difficult but very doable. Pulling users away from their platforms and ecosystems is infinitely more difficult. I think you underestimate the draw the ecosystem has for all the other apps etc for people. This is why it is hard to compete with Google and Apple, it has almost nothing to do with the phone/OS.

I don't think it should be anything more than a regular Android phone with an alternative app store.

Huawei, Redmi, Samsung and Amazon have their own app stores, so why should it be difficult for Epic et al to have theirs on their own phone as well?

Is it not about creating new phones from scratch. It is simply about rebranding or OEMing Android phones with different App stores.

What so difficult about that?