Guacamole is a great project for using VNC/RDP protocols. We have developed our own protocol at Paperspace which we are constantly optimizing for sub-optimal conditions which can include low bandwidth and low-quality (i.e. lots of dropped packets). That said, we are primarily building for a world where access to high quality, fast internet is a reality.

As far as "untethered agility" goes, it was intended to speak to being free to access your computer from any device! Sorry for the confusion :)