It’s based on your Account/AppStore region not the phone. Apple Music, Podcast, Books, AppStore and basically everything you pay with the card linked to your account are based on your Account region.
You can see for example that some regional Playlists in Music (like Siri playlists or Today Hits) are written in the Region language on the cover but the name itself below are written in your phone language.
My account region is French so I get French cover name, French Podcasts or French Books reco. Before it was Portuguese so I was getting Portuguese name and reco.
It’s based on your Account/AppStore region not the phone. Apple Music, Podcast, Books, AppStore and basically everything you pay with the card linked to your account are based on your Account region.
You can see for example that some regional Playlists in Music (like Siri playlists or Today Hits) are written in the Region language on the cover but the name itself below are written in your phone language.
https://preview.redd.it/e9u1hicf9h1c1.png?width=956&format=png&auto=webp&s=0988deb1609da803f82e078f05a1f627c8c2e356
My account region is French so I get French cover name, French Podcasts or French Books reco. Before it was Portuguese so I was getting Portuguese name and reco.