M1 SSD upgrade service up to 2TB – M1 Mango Tech Store
M1 Mac SSD wear probably won't kill your machine - 9to5Mac
There's a way to upgrade an M1 Mac's memory and storage
Mac Studio SSD does not work on NVMe, top-level ARM64 SSD controller in M1 Ultra makes it nearly impossible to swap-out or add raw storage modules - NotebookCheck.net News
M1 Mac RAM and SSD Upgrades Found to Be Possible After Purchase - MacRumors