Audio works with Sennheiser USB-C headsets for apps like Youtube, and also Galaxy system sounds (key presses etc). 

But no audio through USB-C headset for calls, or for Webex (an app for making calls).

I see there are other posts on here suggesting the same problem with other A series models:

https://eu.community.samsung.com/t5/galaxy-a-series/usb-c-headset-not-recognized-for-calls/m-p/66949...

https://eu.community.samsung.com/t5/galaxy-a-series/galaxy-a14-usb-c-headphones-on-whatsapp-not-work...

https://eu.community.samsung.com/t5/galaxy-a-series/make-phone-calls-using-digital-dac-usb-c-headpho...

Is this a deliberate action by Samsung to prevent A series phones being used with headsets for calls? (They seem to work on S series phones). 

Clearly it IS possible as I can hear audio through the headset. So I guess there is a hidden setting somewhere. Can someone develop an app to fix this? As a business user I will gladly pay a few $ for such an app, rather than having to replace a suit of phones just so my users can plug headsets into their A series phones to make calls.

(yes I've tried in Safe Mode,

yes the system setting are up to date,

no the device doesn't show up in Connected Devices, even when I can hear YouTube through it)

Any other tips would be great

Thanks in advance.