S21 Ultra Cannot turn off built in mic and record video

[acs4cert]

This is becoming ridiculous, a simple objective “using an external mic. to record video with the S21 has turned into a science project!”  Come on Samsung!

I was attempting to use an external mic. for my S21 Ultra (using the USB port).  Tied to use pro-Video and select USB as source for the mic., USB as source is greyed out.  Then I downloaded and installed Samsung USB-C app. (because I was unable to record using an external mic.).  No change, USB C as the source is still greyed out, can only record using S21 built in mic.

As a work around I decided that what I will do is record using another device for audio and mix the video from the S21. Mix using Adobe Premier Elements or MS Movie Maker.  So, of course I will want to turn off the S21 internal mic.  So I navigate to settings, Security and Privacy, select Privacy, and then select Microphone access and switch from On to Off.

All seems right until I attempt to record a video (normal or Pro mode).  The S21 will not allow me to record video unless I turn on the built in mic.!!

[Members_DeqDnWe]

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[Members_DeqDnWe]

I have exactly the same with my new galaxy A15. I want to make a video without sound but the camera refuses to work without the microphone!! Why?? Has anybody found something on this? This is ridiculous Samsung, if I had known that I wouldn't have bought this. I bought this phone for the video, and now the phone decides how I have to make the video? Who's the boss, the phone of me?