No there was HPC sku of Windows 2003 and 2008 : https://en.m.wikipedia.org/wiki/Windows_Server_2003#Windows_Compute_Cluster_Server
Microsoft earnestly tried to enter the space with a deployment system, a job scheduler and an MPI implementation. Licenses were quite cheap and they were pushing hard with free consulting and support, but it did not stick.
I have no experience about what you are trying to achieve, but rdma and related technologies (infiniband, qlogic, sr-iov, ROCE) is not it. These are network technologies that permit high bandwidth/low latency data transfer between hosts. Most of these bypass the IP stack entirely.
Infiniband is a network stack that enable RDMA, it’s only vendor is now NVIDIA which acquired mellanox. Qlogic was another vendor, but it got acquired by Intel that tried to market it as Omnipath, but it was spinned off to Cornelis network.
Sr-iov is a way to share an infiniband card to a virtual machine on the same host.
ROCE is an implementation of the rdma software stack over ethernet instead of infiniband.
Yes people left and were not heard at the time:
One of the main developers presented this project at FOSDEM.
https://fosdem.org/2025/schedule/event/fosdem-2025-6196-rewriting-the-future-of-the-linux-essential-packages-in-rust-/
(He is a Mozilla employee but made a point to tell it was not affiliated with Mozilla and was working on it on his spare time)