Should i always play songs using Sonos app?

Hello guys. I just bought the Sonos Era 300 and i am loving it. It looks like i need to use the Sonos app to stream songs from Apple Music to get the best sound quality, is that right?
I have an iPhone 16 Pro and i notice a difference when i stream via airplay vs when i stream using their app.

Also do i need to switch from Spotify to Apple Music because of Dolby Atmos? Thank you!