Bluetooth: fixed settings for certain devices

Hi folks,

I am not quite sure if my question belongs to KDE or to linux in general, so I just give it a try here:

I have a Plantronics Buetooth headset that I like to use for conferencing on the PC. The simple problem: When I switch on the headset it connects to the pc as a High-Fi device with A2DP, but that device has no microphone. I can change the profile to headset with the hfp protocol using pavucontrol. This device has a also microphone and then I can use the headset.

The Problem: I cannot do all that when a call is just coming in. Instead I want to connect the headset directly as a headset device. Is that possible?
The preferred solution are some magical entries in some config files. Second best would be a little script to change the profile that I can start with a double click.

Thankful for any hint, Paul

I also have a Rode NT-USB Mini microphone that would be even better that the headset. But there’s a problem, too:
When I connect the mic to the PC the microphone is detected immediately and working.
BUT: The microphone also has a control output using a 3,5 mm jack for a headphone, and when I connect the microphone to the pc the output is automatically switched to that output.
I like the feature that newly connected devices become the active ones, but not with this microphone output.
What can I do about it?