In normal conditions the sounds are recorded correct?
Have you tried to record using a different application, like *no-support-for-this-app-on-this-forum*?
It is possible to test this scenario without any protective case installed on your phone?
I guess the protective case is vibrating and cause the distortion.
Maybe the microphone is too sensible to record heavy noise.
Because I have Mi 10 (normal/umi) I guess is irrelevant how good my phone is recording videos.