Comment by runjake

Something like DeX is already lying dormant on iOS and it's already enabled on iPadOS.

But, if you modify the MobileGestalt plist on the iPhone, you can enable the "Stage Manager" desktop mode and connect a mouse, keyboard, and monitor and you get a desktop from your iPhone.

Caveat: due to artificial reasons, it's not really usable for daily driving due to the way the hacks work, but Apple could certainly make some trivial changes and get it going.

https://github.com/frs0n/GestaltEdit