I have a problem with the video audio on this Iphone SE 2020

Hi,

When I record a video using the camera app, the audio goes up and down quite often. Even, the 'background' noise is really loud that it disturbs the actual audio of the video.

But, when I record my video using any other app such as Tiktok, Instagram, Whatsapp, or Snapchat the audio is completely fine.

It only happens when I use the Camera app from my phone itself. I have tried several things such as restarting my settings, turn off the noise cancellation.

Can you help me out? Thanks in advance.