Full disclosure, I have used xrdp with RHEL/CentOS for years, but I have not used it with Manjaro. Note that in the ArchWiki article it states TigerVNC is used for the back end. You might want to consider just using TigerVNC to open a graphical desktop for your Manjaro machine.
I do not have admin access to the windows machine, so I can’t install TigerVNC. So I might be trying to utilize either TigerVNC or the mentioned xrdp (sounds more like it by the name) accepting connections via the default “Remote Desktop” Windows App I guess.