Literally nobody on YouTube, certainly not Linus, has attempted to upgrade the storage modules with a supported configuration that the machine is shipped from the factory with.
There isn't a single other SSD controller on the market that knows how to work with arbitrary quantities of NAND flash chips because it's an unnecessary engineering challenge, I don't know why anybody thinks it's remotely reasonable to expect Apple's to be different.
There isn't a single other SSD controller on the market that knows how to work with arbitrary quantities of NAND flash chips because it's an unnecessary engineering challenge, I don't know why anybody thinks it's remotely reasonable to expect Apple's to be different.