One redeeming NAS feature for Minis is Thunderbolt 3 or 4, which could allow you to run a PCIe 3.0x4 bus to an external enclosure for hosting a bunch of disks. You are not going to be breaking world records with that kind of a restricted interface but it’s fast enough for a basic NAS.
However, per feature requests here, PCIe tunneling is not supported in TrueNAS Scale 24.10 while it was supported in 24.04. I’m not confident that tunneling would be included in 25.4 either.
Connecting to a external array via USB is also certainly possible but fraught with many risks, such as TrueNAS not being able to address disks directly the way it can via PCIe / Thunderbolt.
While the idea of a MacMini running a NAS is attractive - low power, pretty enclosure, just add a thunderbolt JBOD tower to hold all the disks, I doubt it’s as practical as finding a quality supermicro enclosure and going from there instead.