I use the Jabra with iPhone 11 and Mac (year 2019), mainly for Skype and GoToMeeting.
Bluetooth connection in parallel to both devices works without problems, range in the flat approx. 12m.

The call answer button on the Jabra does not work with Skype for Mac. The volume control works.
If the call comes in on Skype on the iPhone and Mac at the same time and the Jabra is only switched on in the meantime, then the Jabra automatically accepts the call on the iPhone.

When I answer the call on Skype on the Mac, Spotify or Youtube continues to play in the browser.

With GoToMeeting I recently have the problem that the Jabra is only recognised as a microphone after switching it off and on again.

Phone calls with iPhone 11pro work perfectly, Bluetooth without dongle on notebook (Acer with Windows 10) also works.