The bug
On Bedrock Edition in 1.16.200, it was made that when you adjust a sound slider of a category in the settings when not being in a world it plays a sound of that category. However this isn’t a thing on Java. Since this was added in 1.16.200, it is a valid parity issue.
Ambient/Environment plays cave sounds.
Blocks plays the sound for placing grass blocks
Hostile creatures plays zombie sounds
Friendly creatures plays cow sounds
Players plays eating sound
Jukebox/Note blocks plays guitar sounds
Weather plays lightning bolt sounds
How to reproduce:
Don’t be in a world
Go into the the Music & Sounds Options menu
Adjust any of the sliders
❌ It doesn’t play a sound of that category.
I can confirm that sounds are played when adjusting the sliders in Bedrock, but not in Java.