I would go so far as to say that earth based calendars might benefit from starting at an equinox instead of the height of (winter or summer), months should start at new moon, and days should start around sunrise instead of the middle of night. Space travellers will need a more universal calender.
Permanent, year-round standard time is the best choice to most closely match our circadian sleep-wake cycle
I actually like the start of the year being close to the winter solstice (better if on winter solstice) because, for us, that is the start of a new cycle on earth and not in the middle of a transition like the equinox is.
Fair enough … in some places the habitat “comes alive” around March 21 and seems like a start of something new as opposed to everything frozen solid in Jan, but advocating for marking the rebirth of the sun has been working great for millennia.
That is a good argument for the spring equinox. I don’t think there is an absolute start and end of a year, just a continuous cycle. So any start and end point is just arbitrary.