Re: NC700 - Found a working bluetooth dongle for Windows device!!!
I'm using the "MPOW USB Bluetooth Dongle Stick Bluetooth 4.0 adapter" as it is called on Amazon.de (link). I'm testing this now together with the link to the BT software stack and driver as suggested by MaxXD (kudos). I initially only installed the required Broadcom BCM20702 driver and continued to use the BT software as exiting on my laptop: this did not solve the problem; I had to use the other BT stack.
Double tapping - in my case - does not mute the microphone when in a Teams call.
So far, this MPOW now seems to work fine with Team (yesterday also with GoTo meeting), but time is too short to be 100% sure.
I also bought an "Asus USB-BT400". This one also uses the Broadcom BCM20702 chip, so I expect it to work as well as confirmed by others in this thread. I tried it just replacing the driver while keeping the default BT software on my laptop, which did not work, so you will need to use it with the full BT software I would guess. Not checked yet.
The 'different beast', on second thoughts, might have been a poor choice of my words. No negative feedback intended. I wanted to say that the "1Mii B10 USB Bluetooth Adapter for PC Bluetooth 5.0 Audio" (link) is not a functional replacement for the BT dongle in my laptop or the MPOW one. If you plug it in a USB port, an audio device shows up in Windows (it is said to work with MAC-OS as well). It cannot be used for a BT mouse for example; just audio. It has some nice other audio related features as well. In Teams and other communication programs you can select the related 'speaker' and 'microphone'. You are not using the BT software from your laptop. The dongle has a small button which is used to initiate pairing. You need to double click this button to put it into 'Call' mode, in which mode the microphone works. I have been using this successfully with Teams for a day or so. The need to double click it not so practical in my view. But, if you want to keep using your existing BT, this is a good solution. Double tapping the headset did not mute the mic.
For now, the MPOW dongle seems in my case to be the more practical workaround until Bose fixes the root problem (!)
I did not buy the MPOW BT5.0 one you mentioned, as far as I can see, that one supports indeed more than just audio. Given the advantages of BT5, this might be worth a try!