Bluetooth microphone Bug on iPhones

On iOS 15 there's major bug with the bluetooth microphone quality when recording voice memos, calls...

I tried 5 different devices. All of them give me same poor low quality (muffled) voice recordings.

Devices I tried:

Sony wf-1000xm4

Soundcore liberty air 2 pro

Jabra elite 7 pro

Jabra elite 75t

Anker soundcore boost

With all devices the voice recording are extremely poor, dull and low in volume.

I tried a colleagues' iPhone 13 pro and another ones iPhone 12 and an iPhone 8. Same result.

Then I tried the same test on a Samsung Galaxy s10 5G and the voice recording came out crystal clear.

I guess nobody mentioned it before, because most people would think it's normal this way. But only if you compare the 2 recordings side by side you notice There's a huge problem with the iPhone Bluetooth mic recordings.

Seems like the bitrate ist very low when you record voice messages over Bluetooth devices.

I'm on iOS 15.3 but noticed it right from the start of purchasing the phone.

So I went to an apple store today and we tried the same test with another iPhone 12 and an iPhone 8 SE. -> Same results. Poor quality(muffled) of voice memo on iPhone. Much better quality on android.

Then we did the test with a pair of airpods pro and let another apple creative hear the recordings but blindly! So he didn't know which recording was made on which phone (android or apple). Without hesitation he said the android sounds better.

Then we assumed that it looks like there's a filtering/processing going on on the recording of the iPhone like when you noise cancel the background noise. On iPhone 12 you have the abilty to turn of noise cancellation but not with the iPhone 13. So we turned it off on the 12 and the sound quality of the recorded voice memo was slightly better, but not as clear as on Android.

Any ideas or solutions on this bug?