I have not tested BubbleUPnP on Chromebook for a while (I have a very old Chromebook probably not up to date), but I do not think the networking limitations of its Android subsystem have changed.
Namely the inability from the outside world (renderers for BubbleUPnP) to connect to BubbleUPnP's http server for streaming the media it manages (local
and cloud). That's because Android on Chrome OS does not have its own ip address on the local network, thus no machine from the local network can connect to it.
Android on Windows 11 has the same issue. This sucks.
This cripple the app immensely and make it unusable for most cases.
Though I should get a cheap Chromecast device to check the current status and if some work-around (that will not fix everything) are possible.