[xondono]

There isn’t a duopoly, it’s just that the two top contenders are way ahead of the rest, so wanting that niche feature requires a big sacrifices.

Nowadays it’s not even that hard to build your own phone, but it’s not going to be a slick smartphone for sure

[debazel]

It's not possible to build your own phone in most markets anymore. Without iOS or Google Play Integrity you won't be able to install or run essential apps required for banking, taxes, healthcare, public transport, etc. This makes it impossible to compete because anyone who buys your phone are required to also buy a secondary Google approved Android or iPhone to lug around in order to function in society.