Please note that Røde’s Soundfield Plugin takes an Ambisonics Soundfield as input and converts it to stereo (or mono or 5.1 or something). You can then use the output of the plugin in Ardour using the regular (VBAP) panners. Ardour’s output will be Stereo or 5.1 or whatever you chose.
The link you posted (https://community.ardour.org/ambisonics) describes the process of taking mono, stereo or Ambisonics sources and arranging them with Ambisonics panners. Ardour’s builtin panners have to be deactivated. The output will be in Ambisonics B-Format which you can decode with ambdec for playback on your speaker setup (or for binaural playback).
I use the Røde Soundfield Plugin to decode recordings of a Zoom H3 for work in Mixbus, which is stereo only. The Plugin works fine on AVLinux 2019 via Carla’s Wine bridge.
If you want to try it out, Røde offer some sample recordings that you can download. I’d highly recommend doing that.