@andy6tins
For me, the short winter days seem to have no effect on how much energy I have.
Where I live, right now (beginning of January 2021), the sun comes up around 09:20 and goes down around 14:40. I go to bed around 23:00 and get up at 07:00. So about 10 of my 16 hours awake are spent in the dark, but it doesn’t affect me at all.