At Teleport we had a lot of requests to support Windows / RDP. We ended up building our own Go/Rust Client into our server/web client. This gave more control over the RDP protocol and authentication.
OP here, thanks for posting! Happy to Answer any questions. I have to give our a shoutout to Alan at Teleport for all his work on Passwordless and his work to make Passwordless / TouchID work with MacOS CLI https://github.com/gravitational/teleport/blob/master/rfd/00...
https://goteleport.com/blog/desktop-access/ https://goteleport.com/blog/secure-rdp-client/