Using a valuable rate-limited post to say: you can. USB4 mandates direct host-to-host connectivity. If you bought an Intel laptop with 11th-gen/Rocket Lake (March 2011) or better, the cpu has built-in 40Gbps USB4/thunderbolt that can do host-to-host, although not every laptop implements the actual PCIe side of that. This has been support in Thunderbolt since Linux 4.15[1] in 2017.
Alas more generally, things aren't super hot for USB4 devices & things like ethernet integration. USB4<->ethernet options are still very very limited. Paying multi-hundred dollars for 10Gbe is... unfortunate. We have a long way to go before USB4 IP starts coming to actual devices; the hubs shield us from the obviousness of the need by being, in effect, a far-away mini-southbridge with wild behavior-switching on each port. So it's easy to keep doing what we're doing. But eventually I hope we stop using bridge chips and have some re-usable PCIe tunneling or other just better actual USB4<->flash or USB4<->ethernet chips that really try to be modern. It'll be a while.
As another poster says, cable length is short. 2m with active cables. USB3 had a lot of great cables with active repeaters built in (for a while there my desktop was 10m away from my desk), and I admit, I'm surprised I haven't seen this happen yet for USB4, but it should. One of my desires from USB is to make a longer range USB spec. Please give me 20Gbps over 10m? But for people just wanting to plug their laptop or desktop into their NAS, or wanting to direct-attach a mini-cluster together... heck yeah, USB4 is there for you, today.
Alas more generally, things aren't super hot for USB4 devices & things like ethernet integration. USB4<->ethernet options are still very very limited. Paying multi-hundred dollars for 10Gbe is... unfortunate. We have a long way to go before USB4 IP starts coming to actual devices; the hubs shield us from the obviousness of the need by being, in effect, a far-away mini-southbridge with wild behavior-switching on each port. So it's easy to keep doing what we're doing. But eventually I hope we stop using bridge chips and have some re-usable PCIe tunneling or other just better actual USB4<->flash or USB4<->ethernet chips that really try to be modern. It'll be a while.
As another poster says, cable length is short. 2m with active cables. USB3 had a lot of great cables with active repeaters built in (for a while there my desktop was 10m away from my desk), and I admit, I'm surprised I haven't seen this happen yet for USB4, but it should. One of my desires from USB is to make a longer range USB spec. Please give me 20Gbps over 10m? But for people just wanting to plug their laptop or desktop into their NAS, or wanting to direct-attach a mini-cluster together... heck yeah, USB4 is there for you, today.
[1] https://www.phoronix.com/news/Linux-4.15-Networking