I don't see how this can be an issue with the OS itself. In fact, you mention using the "generic" audio driver to correct the problem which would suggest the one included with the OS works fine, and perhaps the 3rd party applet/drive is at fault.
You really gave us little to go on. What hardware? What sound device?
I have W10 on this system and go back and forth with Pandora, YouTube, other sound files and OS system sounds and my sound levels typically are consistent. But it must be noted - especially when it comes to recorded videos that it is up to the person doing the recording how they set their mic input levels that determines how the volume levels will be during playback.