Yes, location services must be enabled both in the PokerStars app settings and on your device system-wide for the app to access your location.
Location services must be enabled:
The PokerStars app cannot access your location unless both permissions are enabled.
You can enable location services for the PokerStars app by granting permission in your device's app settings.
Follow the steps for your device's operating system:
Location Services must be enabled at the system level on your device before the PokerStars app can access your location.
Follow the steps for your device's operating system: