Phone mechanisms which worked for me:
- the original Motorola StarTac "Star Trek Communicator" flip.
- the Danger Hiptop / Sidekick II rotating screen-over-keyboard
- the Motorola Droid slide-out keyboard
- the OnePlus 7Pro slide-out selfie-cam
Only that last one was motorized, but mine is still working. Holes and divots and islands and any other kind of screen interference is strictly inferior.