This is a first working implementation of scripting using the new mod-script-pipe in Audacity 3.4.2. It expects Python 3 and utilizes a Jinja2 template. Edit the JSON configuration as desired. All tones in each "mixed track" configuration are written to an audio file ('.ogg' in this case).
Audacity should be open and blank (no tracks). The existing Jinja2 template creates each of a duration of frequencies, then combines/mixes them into a single track, writes this to a file containing the name in JSON as tone_data.mixed_track and then deletes the track from the window.