I used to want 10ge on my NUC then I bridged it via Thunderbolt to a machine that does have 10ge and that has been satisfactory.

Does Ethernet over TB only pretend to be 10GbE but is actually faster or does it only use 10 Gibbons of the available bandwidth?

People have gotten 17 Gbps so it's not limited to 10.

Yeah I actually expected it to be 20 but it’s just short of that. Not complaining.

There are some small form factor machines here with 10G but they aren't cheap

https://mitxpc.com/collections/mini-server

The R86S might be worth a look for you.

I did look at the R86S with interest when the STH article came out but the 16G max of RAM is a limitation. 32 or 64GB would be ideal to be able to run a bunch of VMs.