Even at half insolation, even with dust storms, you are still going to be get quite a bit of free lighting from the sun. It takes a whole lot of power to get 500 watts per square meter lighting hundreds of acres worth of crops. That’s 2 megawatts per acre that you get to save, assuming 100% efficiency lighting. Probably closer to 10 or so megawatts per acre in capacity, though usage would only be about half that, as you turn them off at “night”.
You can generally feed about 2 people from an acre of crops(it’s a complicated issue, to maintain a typical American’s diet requires more like 3 acres per person), let’s say that we are much more efficient, and we feed 5. That’s a megawatt of power required just to power the lights to make the food for one person.
Silica glass is pretty good at screening out UV. Plants may not mind being grown in much lower atmospheric pressure, with higher CO2 content. Fusing together Martian regolith into glass has some challenges, but so would digging caverns beneath the surface large enough to provide the room for agriculture.
It will take a fair amount of trial and error to figure out the best way of producing food on Mars (assuming we ever get that far), but having a much lower cost of the infrastructure and power required for farmland may make up for the difficulties.
They would not be in temporal isolation. They would have clocks, they would have commerce, they would have times that they start and end work.
Having more exposure to the Martian day would tend to cause people’s rhythms to become less attuned to Earth time, not more.