I’m curious, does the red series switch ground via both the green ground screw terminal and the switch yokes?
Currently I see romex coming in. The bare copper ground is tied to the metal box directly and the old light switch with the green ground wires snipped off.
Yes, the mounting screw tabs are electrically connected to the green screw. So in theory either will provide a safety ground. However the green screw will provide a more positive connection as the mounting screws do not have as good conducting path.
My house has mostly BX (aka armored cable) so many of my switches & receptacles use the tab for safety ground.