FP5 TikTok audio for self recorded videos too low - Videouploads out of synch

Help Fairphone 5
1

  1. When I stitch videos on TikTok, the audio of my recording is massive too low. When I speak louder, this does not make it as much louder as I speak.

  2. When I record with the camera alone, audio seems fine (not brillant but fine and loud enough). When I upload to TikTok, Audio is out of synch.

Thanks from Berlin.