In Google Home there is this feature called "speaker groups" which allows you to play the same music simultaneously on several speakers, in several rooms in the home, etc.
I use this to play music in my entire home. However, there are still some rooms to which I would like to add speakers.
AFAIK, only Google Home speakers and Chromecast devices can be added to speaker groups at the moment.
I could go out and buy even more Google Home devices, but I have some spare Android devices and good speakers to hook them up to, so I figure that would be cheaper, better (in terms of sound) and environmentally friendlier.
So basically, to be clear: I want to have an Android phone hooked up to a speaker behave pretty much like a Google Home, and play audio in a room. I want to be able to add it to my speaker group for the entire apartment, so that it can play music along with my real Google Home/Nest/Chromecast devices, in sync with them.
It seems that there previously was an app that made an Android device emulate a Chromecast. That app was called CheapCast but it now seems to have been taken down.
I also found an app that did let me receive Chromecast on my Android, but it did not show up in the Google Home app so that it could be added to a speaker group.
Is there any way to achieve this? I can use root, Xposed Framework, Magisk modules, custom roms, whatever is needed.
The Android devices I have lying around are running Android 9.