AirPods Pros seem to be missing some features

I have just bought a second hand pair of AirPods pro that are still under warranty.

They sound pretty good and feel very comfortable but some of the features appear to be missing. Most obvious to me it auto device switching doesn’t seem to work. I have paired with my iPhone (running iOS 15.1) seemed fine. However when I try to auto connect my iPad pro it will not connect. The only way I can connect is to manually disconnect from iPhone first and then manually connect to iPad. When I then try to connect back to iPhone it doesn’t work at all and I need to unpair and repair. This isn’t the seamless Apple experience I’m used to. Looking online it seems that there should be a setting under the Aripods in the Bluetooth menu to set auto connect behaviour for the device. This is missing from mine. Doesn’t work wit my iMac either without disconnecting and repairing.

All devices on latest OS and firmware. All devices on same iCloud account.

Driving me mad. Still under warranty so think I may need to make a long trip to the Applestore.

Any help that might save me a trip appreciated.

Also I’m not sure that the noise cancelling or spatial audio are working. Settings are there but not sure they have any affect.