I would not generalize it for all new Nokia handsets on Android One. Nokia 5.1 is on Android One (though it's still on Android 8) and it allows to format SD card as adoptable storage without tricks. I used SD card as adoptable storage on 5.1, but it was PITA. When Play Store was updating apps they got moved back to internal storage. I got tired of the exercise of moving apps back to SD card after every update.

 

Probably there is some reason to doesn't allow formatting SD card as internal on 7.1. You can try formatting SD card as adoptable storage using adb:

 

adb shell

 


sm list-disks

 

<disk id, something like disk:179,128>
sm partition disk:179,128 private