M4 Mac Mini SSD modded from 256GB to 1TB — modder solders higher-capacity NAND to the removable SSD module
M4 Mac Mini SSD modded from 256GB to 1TB — modder solders higher-capacity NAND to the removable SSD module

www.tomshardware.com
M4 Mac Mini SSD modded from 256GB to 1TB — modder solders higher-capacity NAND to the removable SSD module

You still need to source blank NAND modules, have a spare machine on deck, and be able to solder them.
Yeah not feasible except for a tiny minority. I wonder if people would offer this as a service though. I presume the actual modules are cryptographically paired to the Mac so you can't just get entirely new modules.
I could totally imagine posting my module to someone else to upgrade though.