How to disable activity sharing with Siri?
To disable activity sharing
1. Open the Bigin app on your iPhone.
2. Tap the
More 
icon at the bottom right of the screen.
3. Select
Settings 
.
Under "Manage Privacy", you can find the title "Privacy & Security".
4. Tap on Privacy & Security > Share Activities with Siri.
5. Tap the
toggle switch
to disable activity sharing with Siri.

Note: Once you've disabled activity sharing, your Bigin app usage pattern will stop being shared with Apple.