Problem
With the Bluetooth drivers provided by Dell for the Dell Wireless 1820A Bluetooth 4.1 LE, Apple Airpods Pro can be connected successfully, but sound playback is not possible. While connected as an audio device sound just plays over the laptop speakers and the device does not show up in the Sound Control Panel.
Solution
Download a feature complete driver from Lenovo...
Driver can be found here: https://support.lenovo.com/nl/en/downloads/DS104776
This works when your Bluetooth is provided by the: Dell Wireless 1820A Bluetooth 4.1 LE because the driver package that Lenovo provides supports many Broadcom based Bluetooth modules. I was able to find out from the driver bcbtums-win8x64-brcm.inf file for Broadcom devices that multiple Dell modules are supported.
bcbtums-win8x64-brcm.inf
Long story short:
Hope this helps someone out, it was quite the adventure to find this fix but at least now I can use these earbuds on this laptop.
Here is the full list of Dell Bluetooth modules that are potentially supported by this driver installer.
My laptop is saying that my airpods are connected to my laptop but they're not because the sound just continues to come out of the laptop instead of the headphones.