https://wccftech.com/mac-studio-ifixit-teardown/

The Mac Studio was finally in possession of iFixit, and right off the bat, we get a closer look at its innards, revealing some interesting choices made with the storage. Though users can easily swap out the module, and there is also a spare slot to expand it, increasing the internal memory is not as easy as it looks, as you will soon find out.

Since the unified RAM is a part of the M1 Max, upgrading it will not be possible, as shown by iFixit’s teardown. Thankfully, Apple was kind enough not to solder the storage to the logic board, as it is easily swappable once you gain access to the machine’s innards. Sadly, though there is an extra storage slot available, increasing your storage is more than complicated, as iFixit reveals that swapping one Mac Studio storage module with another one kept giving DFU configurator errors.