Cannot pair iPad to iPhone through Bluetooth

Since last upgrades my iPhone SE with OS 17.3 and my older iPad Air 2 running OS 15.8.1 will not connect via Bluetooth. Both devices show up in the “Other Devices” area but they will not pair. My phone tells me my iPad is not compatible.

I do not have any iCloud issues but phone calls made on my iPad using Bluetooth to connect with my phone consistently drop. On both devices, I have rebooted, turned off & on Bluetooth and Reset Network settings but I still have the problem of not being able to pair the two so now I wonder if my iPad has become a legacy device? Any help or advice is appreciated. Thank you.

[Re-Titled by Moderator]