But from doing it on Linux I can tell you that it will probably not be simple and intuitive and there may be some jargon and non-obvious settings involved.

Drifting but I don’t think sound on Linux is straightforward. There is ALSA, PulseAudio, Jack and GStreamer for a few components that may be involved and there are many possible setups (on which I'm easily confused).

My desktop set up is complicated by me using Rosegarden and Jack for MIDI via external (one keyboard and one module) devices. I’ve found Cadence (which will set things up in the background on log in – I don’t need to use the interface each time) provides me with the simplest way of having Jack and PulseAudio working together nicely. Perhaps PipeWire would also work but I’ve yet to try it.

(For MIDI playback on other Linux things, I use Audacious which just needs a soundfont [I use Merlin Gold) provided which is simpler than trying to set up a software synth like timidity or fluidsynth)

Getting back a bit more on topic. On my Desktop, just leaving Audacity’s devices as “system” will work for me. That will use the current system defaults (in my case, that’s nearly always a Yamaha mixer) but I could try to be more specific. With my set up and the mixer, playback and recording are called “PulseAudio Jack source” and “PulseAudio Jack sink”