I happily booted and ran an Intel Mac mini using a 4TB drive in a Thunderbolt 3 enclosure, and I do the same for an M4 Max Mac Studio using an 8TB drive in a USB4v2 enclosure (OWC Express 1M2 80G).

You'll just have to be careful to match the enclosure to the ports on the system. The base-model M6 Mac mini still uses Thunderbolt 4, so a USB4v2 enclosure would be wasted.