This is really what is needed. They could easily use the buttons along one long edge of a Max model as magnets to hold and charge the Pencil.
Dex on the iPhone is an unfortunate pipedream. Whilst the iPhone is capable of running say iPad versions of apps and Stage Manager Apple would much rather sell you an iPad to do the same job.
I personally would quite like the option of a plastic back to bring the costs down and up the durability. The back panels on the S21FE were solid and lovely to hold; I'd want to see something like that, a return of the 5C aesthetic and colour options to match.