I've been looking at some Linux based phones and one thing that caught my eye was a Pi based build.

This makes a lot of sense to me in many ways as the smaller Pi's carry a lot of power and expandability, however it was based on an older 3b platform and consequently very bulky.

Currently, my searches online have led me mainly to boards that support CM4 but also have ethernet ports etc (adding build) or use USB/pinouts with no CM (Compute Module)connector.

Anyone know if there's a small board that can support cellular connectivity with a native CM connector?

Also, any way around the lack of SDCard support for Pi's that boot from eMMC (would like eMMC for the OS and SDCard for larger stuff, pictures etc)?

I'll add: the board doesn't have to be credit-card sized. Something along the lines of an average smartphone so I can fit a decent LCD would be fine, just no Ethernet etc making it too thick