Okay, thank you #fediverse! My #pipewire / #cider / #ubuntu woes are solved 😎

Thanks to @stevenixon, @BradRubenstein and @korvroffe for suggesting a combination of mkchromecast (to discover and connect to the chromecast devices on my network and create a virtual audio device) and qpwgraph for building a virtual patch bay to route audio from apps to devices (similar to loopback on macOS)