When adding Amber to obtainium it should automatically show only the apks that are compatible with your device, then you just need to choose the play version if you don't want to use the ntfy application to handle your push notifications.
If you want to use ntfy them download the free version.

https://image.nostr.build/a37535143487fceb94391ec0c588b672278d25498e3a073258a60481518bd9b6.png