As a Roblox developer, it’s currently not possible to control or check Voice Chat Volume via scripts.
If Roblox addressed this issue, it’d allow me to have more precise control over the voice chat experience in my Experiences. It would allow me to create a cohesive and uniform volume control panel, which would prevent players from having to dig around through menus to make their audio experience to their liking.
Edit:
It could also be useful for game audio attenuation to improve the conversational experience in games. But, that may go beyond the scope of “Setting volume via script” and be more akin to asking for a way to have it set to a sound group so we can use compressors or equalizers.