Note that you can do point-to-point network links directly with thunderbolt (and usb4).
https://support.apple.com/guide/mac-help/ip-thunderbolt-conn... etc
https://support.apple.com/guide/mac-help/ip-thunderbolt-conn... etc
You'd also mostly be limited to short cables (1-2m) and a ring topology.
This is my firsthand experence trying to get some tablet motherboards to link up and work as a proxmox cluster w/ TB3 as the link between nodes.