OK, it's not really a "hack". Probably more correctly a "little known option"!
Have you run into a problem trying to slow down a video to better enjoy something that happens quickly? Say, making the dry Model's "fall" into a Dunk Tank take several seconds instead of just a fraction of one?
Does the screen freeze and then get jerky and unwatchable?
Go into VLC Settings and turn OFF "Time-stretching audio"!
Older devices like my phone spend way too many processor cycles trying to keep the audio from going up (faster) or down (slower) in pitch and you likely don't really care.