Thunderbolt 3 Ethernet not working after windows 1809

Question

It would seem that from 1903 onwards, thunderbolt 3 networking has been broken in Windows 10, still broken in Build 2004. We have a QNAP TVS-872XT NAS, we see about 1000mbps write and 1400mbps read on our 13" Mac Book Pro. We have two Windows 10 PC's with thunderbolt, one Ryzen, one Intel, both tested with an external thunderbolt drive with 2m active cables get's 1.4gbps read and 1000+ write speeds.

It's not the cables, both are tested and pass because of the external thunderbolt drives and speeds.
It's not the NAS because it works perfectly with the Mac Book Pro.
It's not the Thunderbolt cards on Windows because they work with the external thunderbolt drive.
It seems to be Thunderbolt Ethernet, it's fundamentally broken, 65mbps transfer speeds copying from, and trying to copy to it drops to 0mbps and then nothing.

Many folks have exactly the same issue here
https://forum.qnap.com/viewtopic.php?t=150261

QNAP appear to have reached out here:
https://social.technet.microsoft.com/Forums/en-US/1a5a1e19-bf0f-444e-8379-0dbf87e69f1e/the-performance-of-samba-in-write-is-not-well-over-tbt3-after-upgraded-to-version1903?forum=win10itpronetworking

I'm at a loss, I don't think there is much more I can test or try, both windows machines have exactly the same problem, clearly, thunderbolt 3 networking on windows is now broken, is there a hotfix available.

Answer 1

Works on Win 8.1 pro, you can follow the instructions for bridging, I was able to create the first bridge (3 computers), then I extended the bridge to a computer on the edge.

It appears you can bridge in additional computers indefinitely

Answer 2

If anyone is still listening on this thread....
Follow up:

'Bridge Connections' works on TB3 adapters on 20H2

Answer 3

Retried to bridge tb3 connections in 20H2 Jan 2021 update, once again NOT working