postmarketos is beginning to support cellular capabilities. You may not have to wait a whole lot longer.

There is. You just don't want to spend the money or use the phones/tablets from said competitor.

I'm personally a big fan of iOS, but coldpie's (and others in this thread) needs seem to be in third party browser capability that doesn't exist in iOS so with that, I wouldn't recommend it to them. I don't think it is a matter of spending money on competitor's devices so much as competitor's devices don't meet their needs.

It'd be acceptable if we could run code on it, as root, like we actually own it.

iOS doesn't allow anywhere near the level of customization that Android does, nor does it allow 3rd party browser engines at all, however there's Sailfish OS and maybe the Librem 5 soon.

iOS doesn't allow you to use other browser engines.

iOS is not a competitor for my needs.