I do sound design work for media composers and very often I demo the work in realtime during a video call. The problem is that Google Meet, Skype, Zoom, etc don't have good enough audio quality for this. So in parallel with the call I stream high quality audio from the DAW to a web UI the service offers.
I think you could use https://sonobus.net/ for this purpose. It is based on AOO and has a very nice and easy-to-use UI. You could run the SonoBus plugin in your DAW and your clients could listen with the standalone. Just like AOO, SonoBus supports both Opus and raw PCM. Opus at 128 kbps/channel is pretty much transparent. With PCM you might run into packet loss issues.
(AOO has an option for resending lost packets which can be used to create very stable PCM streams. However, I'm not sure if SonoBus actually supports this option...)
That being said, Listeto looks very neat and the pricing seems reasonable. Is there a particular reason why you want to move away?
In the future, I want to add a client plugin and standalone, probably with JUCE.
I'm not sure how useful a GUI would be for the server, though, because it typically runs as a service/daemon.