Issues with Xbox game bar?

I tried to record a lecture instead of a game but it should work in any instance. My internal audio was not recording until I turned my mic on. The issue is when my mic is on, both internal and external sounds and audio is recorded. I don't want external audio to be captured when I do the recordings. Is there a way I can fix this because if I didn't turn my microphone on, the recording should capture internal audio. However, it does not. Please let me know if you guys have any solutions regarding this issue and let me know if you need any clarification. Thanks.