Mangosmiley159 I just tried this and was not able to reproduce your issue (on a Pixel 6, not a 4a, mind you).
When I clicked on the screen recording quick tile, it asked me whether I wanted to record my microphone, my device audio, or both. I selected device audio and it worked as expected.
It would be best to have someone with a 4a try to reproduce this, however, just to rule out any device-specific quirks.
For now, may I recommend some basic things like rebooting your device?