Unable to fix audio issue with QuickTime screen recording on Sonoma 14.4

Hi. Recently, I recorded a video of my macbook screen using quicktime player. However, I realized that it didn't pick up some audio (except voice).

Now I have Sonoma 14.4, installed.

Why the audio recording was unclear? I only ear my voice, but no other sounds.

Tanks

[Edited by Moderator]