Accessing a Linux machine from Linux/Windows via RDP is not fun. Accessing a Windows machine from Linux/Windows via RDP works excellent - I use Remmina on Linux, but there are ofc lots of alternatives, as usual.

Points on accessing a Linux(Fedora/KDE Plasma) machine via RDP:

  - as I understand it, you cannot open a new session, you can only access an existing one -> forget about a headless machine, it will have to render its DE into to void if you want access it via RDP. The work-flow is more like VNC than RDP.
  - X11 has problems, Wayland is definitely worse. Queue the people who will tell me/you that it works fine them. My last attempt on Fedora ended with a "working" setup. Working in quotes, since I had to accept/allow every incoming connection on the host machine (in a pop-up window which auto-hides after a few seconds and did work ~60% of the time), making it useless for the intended use case. You can workaround this by SSH'ing into the machine and accepting the connection somehow, but I gave up at this moment.
  - there is also some fun to be had regarding display resolution and "session passwords", but compared to the fun with Wayland "security" and portals, its manageable