

Jonsbo makes some decent compact nas cases with plenty of space for drives. Look at their N series N3/N4 etc.
matx would be more upgradable than itx, but nobody is making either of them with 10gb Ethernet. So I personally would be looking at full ATX boards so I could add in a nic.
Couple years ago I wouldn’t have argued, but with graphics cards ballooning to 3+ slots, you have to be more careful about which slots on the motherboard have full enough lanes to support your cards. And you have to make sure your motherboard has the full x16 slot in the highest position which is less common on boards with m.2. otherwise there isn’t room for expansion cards