On iOS 14.5, Siri is more open to third-party apps. When the assistant is ordered to start playing a song, it asks which application it should use, while it automatically favors the first music. Installed music applications are offered: Spotify, YouTube Music, Podcasts, Deezer …
After indicating its choice, Siri must maintain the default application, which thus avoids specifying the desired application every time it is not about music (on iOS 14.4 and earlier, always specify ” Start reading ” With Spotify “, for example).
According to my test on the first beta of iOS 14.5, it is not complete yet. Siri sometimes asks me which app I want to play music with, but can’t remember. Apple has a beta test period to improve it.
Note that on HomePods it is possible to replace Apple Music with another service, but in this case, specific support from the services is required (only Amazon Music and Pandora are currently compatible).
Talking of selecting the default third-party apps for Siri, Apple stated in 2019 that Assistant can automatically select the most appropriate messaging system to send messages to a contact (and not always the default messaging app) , But this possibility has apparently never been implemented.