How come this script doesn't customize my chat?

I'm trying to make it so when people under the name of ProCon712 or Jephi chat their chat Color3 value is (0, 1, 1), they have a fun of SourceSans, and the FontSize is 24. There are no errors in the output. The script is placed in Starter player scripts.

local devs = {"ProCon712","Jephi"}
local plr = game.Players.LocalPlayer

plr.Chatted:connect(function(devs)
    if plr.Name == devs then
        game.StarterGui:SetCore("ChatMakeSystemMessage", {
            Color = Color3.new(0, 1, 1)
            Font = Enum.Font.SourceSans 
            FontSize = Enum.FontSize.Size24
        })
    end
end)

The script is a LocalScript.