So I've taken a closer look at the RDP protocol, and I think that RDP is probably the best option. IRIX does have rdesktop, and porting a later version may not be too hard. I'll look into it soon.
XRDP exists for a UNIX-based RDP client, and I think I'll be using that anyways to get a better browser on FreeBSD (since it has an issue with no acceptable browsers that don't require dbus)
I'm the system admin of this site. Private security technician, licensed locksmith, hack of a c developer and vintage computer enthusiast.
https://contrib.irixnet.org/raion/ -- contributions and pieces that I'm working on currently.
https://codeberg.org/SolusRaion -- Code repos I control
Technical problems should be sent my way.