Ziply Fiber is offering 50 gbps home internet connections in some US locations. You cannot utilize that type of speed with a Mac Mini. Even the modest 8-10gbps connections offered by T-Mobile and Google probably require more.
Is this for people trying to start the next netflix out of their garage before they have any money to put the servers in a colo?
Mostly because the base Mini has Thunderbolt 4 which maxes out at 40Gbps. Anything with a PCIe 4.0 x16 slot will take a 100Gbps NIC. 100Gbps is around 10GBps (8 bits per byte plus encapsulation overhead). Desktop CPUs can do AES-GCM at 2.5GBps+ per core and have up to 16 cores and around 50GBps of memory bandwidth (dual channel DDR4-3200), so the NIC still seems like the bottleneck.