A single LPCAMM2 is a 128 bit total memory channel. The M4 uses a 128 bit memory channel.

You can have 2 LPCAMM2 slots for twice as many memory channels, like the M4 Pro.

Yes, I am aware. M4 Max would need 4 LPCAMM2 modules, and a hypothetical M4 Ultra would need 8. This sounds unrealistic (especially 4 modules in a laptop), which is why I mentioned a proprietary connector instead. There is precedence for this type of thing in the Mac Studio where the SSD NAND chips are on proprietary removable modules.