Is it not possible to connect both Apple Music, and Spotify?

My friend told me it‘s possible to connect both so we got the app to better compare between the two. So I logged in with my apple account redeemed plus and then wanted to add Spotify, but can’t see it in the menu. My friend says he has a button to connect apple music on his end. I saw the other version of the app has a button for connecting apple if you logged in with Spotify first so I did that, and tried to connect AM there which only led to the popup „this account is already connected to another stats fm account please concact support“. I am very confused about how this is supposed to work