Trouble unlinking iPhone XR following setup of new iPhone 15

I setup my new iPhone 15 yesterday - an eSim was used and I transferred everything via iCloud. However, despite removing my old physical sim card from the XR and signing out of my AppleID on the XR it is still mirroring actions such as Google device notifications, Chess.com moves on the App and my Sleep schedule alarm. I have started to sign out of these apps on my XR. However, I thought that once the transfer had been made my old XR would no longer function?

I have also not been able to connect my Watch to the iPhone 15. I signed out of the app on the XR and it now shows as not being connected. But it still works and I am not able to connect on the 15.

I have tried to switch both devices off and on again as per other community member advice. No luck.

Any advice would be gratefully received.

Thank you.