Transferring Contacts via Bluetooth

I have a new Panasonic KX-TG9542 cordless phone. Among other things, it has "Link2Cell" which allows you to connect a cell phone to the cordless phone via Bluetooth. It also has a 3000-space phone book (currently empty).

According to the phone's User Guide, I should be able to transfer my contacts from my iPhone XR to the Panasonic's phone book via Bluetooth. I seem to have successfully linked the iPhone to the Panasonic, but when I follow the instructions in the Panasonic User Guide, it starts the transfer but then almost immediately completes with 0 contacts transferred.

One portion of the Panasonic User Guide says, "Some cellular phones may require you to perform an operation on the cellular phone even if you select 'Auto'" (which is what I had selected).

When I go to Settings > Bluetooth in the XR, I see the Panasonic device and it says, "Connected."

Any idea what sort of "operation" might be required to be done on the iPhone to start the transfer of the contacts?

Panasonic tech support is useless. Chat support disconnects after 2 or 3 minutes of "reviewing your problem."