This is a problem that's bigger than Apple, and it's not a problem that will be solved by allowing more stores on the phone - it won't make it somehow "your" hardware.

You can blame Apple for doing this with their phone all you want, but you're fighting against the tide with a shovel. It's an industry standard to lock hardware down to the point where they'd rather the hardware be bricked (the Nintendo Switch and its hardware fuses) than run "libre" software on it.