I know a lot of people have issues with Windows & Bluetooth & Zwift - I did and tried all sorts of different things and different dongles until I stumbled across a web page -
This forum won’t let me post a link so go to the following website :-
thegeekpage followed by a full stop and then com
And search out the following topic :-
I am now 2 weeks of trouble free zwifting and using the CSR4 Bluetooth dongle that many people said didn’t work.
Good luck and hopefully your “Bluetooth receiver is turned off” messages will be a thing of the past.