I'm on it as well. A trick I found for getting around casting devices not showing up, at least in the cast of spotify casting devices a couple weeks back for me

I'm on it as well. A trick I found for getting around casting devices not showing up, at least in the cast of spotify casting devices a couple weeks back for me, was to install the app ControlDLNA from f-droid. Opened it once on the network and magically the casting options appeared and worked perfectly.