> The storage is expandable externally

I have tried a variety of methods of expanding the storage. I bought an M1 system with this very thought.

None of the USB storage devices I tried worked well. MacOS drops every device I tried periodically. Sometimes it would go as long as a week, but I'd have to yank it and plug it back in for it to continue to work. Very unreliable for a permanent storage augmentation.

NFS doesn't work, MacOS issues. Samba has been the most reliable network storage drive method, but it tends to be slow on my middling servers - and I really tried to optimize it.

If you really want to do this, I suggest trying the thunderbolt route.