[MunkDev]

If you want to mute all sounds, use this:

local dummy = false
hooksecurefunc('PlaySound', function(id)
        if dummy then return end
        dummy = true
        local played, handle = PlaySound(id+1)
        if played then
            StopSound(handle-1)
            StopSound(handle)
        end
        dummy = false
end)

If you want to allow unique sounds, like the talking head monologues or any other uncommon sound, but not UI sounds, use this:

local dummy, kit = false, {}
for _, v in pairs(SOUNDKIT) do kit[v] = true end
 
hooksecurefunc('PlaySound', function(id)
        if dummy or (not kit[id]) then return end
        dummy = true
        local played, handle = PlaySound(id+1)
        if played then
            StopSound(handle-1)
            StopSound(handle)
        end
        dummy = false
end)

If you want to mute specific sounds use Kanegasi's solution. They all work the same way.