How do I avoid or remove "hollow" sound from captured recording of streaming audio?

“audio enhancements” can be on by default, and can add a pseudo-stereo effect which has a hint of reverb. If you are recording the speakers (loopback) any “enhancements” are baked-in to the recording.

https://support.microsoft.com/en-gb/topic/disable-audio-enhancements-0ec686c4-8d79-4588-b7e7-9287dd296f72