If Apple’s macOS ran on the iPhone, how would it work?

Earlier this week, leaker Mauri QHD tweeted that Apple is working on prototypes with Apple Silicon-powered macOS running on the iPhone, which would allow a user to plug an iPhone into a dock or monitor, and have a full desktop experience.
iPhone 12 render (image via svetapple.sk)
Jonny Evans for Apple Must:While this is mere speculation and even if the company were to be testing this out it may simply be to test the processor potential, I had to spend a little time imagining how this might work.