My browser / operating system: Windows NT 10.0, Chrome 124.0.0.0, No Flash version detected
The record sound thing for sounds on a sprite isn't working; headphones with a mic, headphones without a mic, no headphones, different computer, nothing, Only the premade sounds work.

Did you allow scratch to use your microphone? (through a pop up) Click the lock button settings icon to the left of the url, then make sure microphone is toggled. If this doesn't work, make sure you have the right input device (for audio) in settings.