On a serious note, maybe just let people work however they like to work?
Dark theme everywhere has been such a blessing for me as it is way less straining on my eyes.
(Almost everywhere, fuck you google calendar. Wish I didn’t have to use you at work.)
Your „free“ option just requires buying hardware that enables all of it and an intensive setup process and knowledge which might be quite time consuming.
It may be a good solution but it’s far from free for many people.
This you?