Adding this to my collection of reasons why remote work is better. My home office has direct sunlight from 10:00-16:00 every day of the year. I've never been to a commercial office that comes close.
One problem is where the window faces. A north-facing window, or a window facing into a hillside or into a courtyard, does not allow sufficient sunlight. In London, my flat is in a Victorian terraced house, and the bedroom I'd use as a home office has a window which only has views of the house next door, and very little natural light. (That said, probably still more natural light than I got in my office, where I'm essentially in a corridor.)
So every winter I actually take a long 2 hour walk during lunch to get some sun. Then I work later once the sun has set.
This should be the standard for all office workers in northern latitudes. But we're so stuck in our ways that we use the same work schedule all year even though the weather is clearly different.
If the 'health' benefit or bio signal for this effect, requires UV radiation then there is very little that can substitute being outside for 1 or 2 hours a day depending on the season.
Interestingly, red wave (IR) light appears to influence cortisol levels but not melatonin. [1] IR also makes it through windows as any cat can attest.
Getting outside for an hour or two as often as possible, regardless of the season, is probably a good idea, but it doesn't appear to be strictly necessary for modulating circadian rhythms.
It was miserable. The direct light was blinding during the summer,and during the winter the sun didn't clear the top of the window so I got direct light straight at either me or my screens. I tried every orientation.
COVID solved that problem but the next step was blackout blinds, which defeats the purpose a little