We have a Chromecast 2nd generation which has indeed the known problem. However when I use Music Assistant from Home Assistant I can cast from my own music collection (flac files).
I haven’t tried yet to cast from Spotify using Music Assistant.
I own an iPhone and casting a Youtube video indeed doesn’t work. This results in receiving an untrusted device message.
Questions now coming up are
- why are some apps still able to cast to a 2nd generation Chromecast?
- are there more apps still working?
Some apps still working is because the authentication is not mandatory.
Screenshot from Tweakers.net discussion: