You do not have any calendar accounts on this device

Yes I do, and permission to access my calendar has been requested and granted. This is on my Samsung Galaxy Tab S7+, running OneUI 4.0 (Android 12).

(No such problem on my Samsung Galaxy Note 20 Ultra 5G, running OneUI 3.1, Android 11.)

Any solution?

I have this exact same issue. Galaxy S10, Android 12. But had it exactly the same under Android 11.

My phone is now also on Android 12 and continues to work with the Companion app. Tablet still refusing to play (just the calendar bit, otherwise OK).