common complaint about movie audio is ‘the speech is too quiet and the action is too loud’. this can be resolved with dynamic range compression or normalization. ffmpeg provides a normalization filter called dynaudnorm which u can use in mpv via --af=“dynaudnorm”.
Yes this has always been annoying with videos in Linux. Pipewire seems to be better about it and there are ways to mitigate it
https://forum.endeavouros.com/t/tutorial-volume-normalization-on-pipewire/22315
Not sure I follow, I don’t think this problem is inherent to Linux. Just the solution described uses Linux.
Other operating systems have more system wide optimizations to compensate for audio normalization