Minecraft fails to identify itself as anything but "java" to pulseaudio on Linux. This results in volume sliders for Minecraft's audio output (in tools like pavucontrol and similar) being labeled as "java" and prevents pulseaudio from distinguishing Minecraft from any other java applications that share the same flaw.
Fixing this would allow pulseaudio to properly remember per-application settings for Minecraft.

The relevant properties being

        media.name = "Playback Stream"
        application.name = "java"

Which can be queried using

pactl list sink-inputs

application.name should simply be "Minecraft", without any version numbers, so that pulseaudio can apply per-application settings properly across all future versions.
media.name can be anything, but it too shows up in the volume sliders and could be more descriptive than just "Playback Stream". Something like the Minecraft version and the name of the player showing up in here would be nice (e.g. "1.19 - Steve")