Podle mě je xrdp pouze brána mezi klientem ve windows a vnc serverem na raspi, aby ses připojil přímo bez instalace dalšího software.
Tohle je info z balíku (viz. Recommends)
Package: xrdp
Version: 0.5.0-2
Architecture: armhf
Maintainer: Vincent Bernat <bernat@debian.org>
Installed-Size: 1464
Depends: libc6 (>= 2.7), libpam0g (>= 0.99.7.1), libssl1.0.0 (>= 1.0.0), libx11-6, libxfixes3, adduser
Recommends: vnc4server | tightvncserver | vnc-server
Homepage: http://xrdp.sourceforge.net
Priority: optional
Section: net
Filename: pool/main/x/xrdp/xrdp_0.5.0-2_armhf.deb
Size: 252086
SHA256: bfad6e551d111620095c966ed3fa25ceaf666ee516415e7a918826c545be9696
SHA1: d099a603ef137235201cdc7de61a5ed4918707e8
MD5sum: 56d0fa7c26fe45f12e9aaf111aa3c89f
Description: Remote Desktop Protocol (RDP) server
Based on research work by the rdesktop project, xrdp uses the Remote
Desktop Protocol to present a graphical login to a remote client.
xrdp can connect to a VNC server or another RDP server.
.
Microsoft Windows users can connect to a system running xrdp without
installing additional software.
tím pádem si lze funkčnost snadno domyslet a těžko to půjde "i bez nahozené grafiky", jak jsi napsal.