i don't have the option to ‘Add Apps’ to my Daughter’s Apple Watch

She has SE watch and no phone, I have an iPhone. Our software is up to date. She is part of the family plan. I have done all the steps like restarting both etc..

When I go to manage her watch there isn’t even an option to Add Apps to her watch. I have many compatible apps but there isn’t even a section to add anything. I specifically want to add Spotify. On her phone she cannot do it via App Store, it says requires a phone.