I have been grappling with this very issue for some time now.
My first work around was to link the SweetFx (ReShader3) effect toggle to the switch. I could tell when the switch was activated by noticeable change in graphic effects. I can also generate a small nonspecific overlay to pop up in a corner of the screen when a switch is active.
I linked the switches to these indicators via VoiceAttack.
Not a bad workaround but it can only tell you that a switch is activated, BUT Not which one. Also, overlays and Reshader3 currently don't work in VR.
I've also used the Conditions logic in VoiceAttack to turn off any active switches when a switch is actuated. Only a fair solution cuz can occasionally get out of phase.
Im currently checking out USB LED light strips with which I can identify any and all active switches with a particular LED. Again, limited utility in VR.