Your poem reminds me of much great poetry and song that expresses this same thing ... the yearly tipping into cold, dark days is not easy for many, but, you are right: root yourself. I remind myself that on December 21, the earth begins to tip back in the Northern Hemisphere toward the sun, and I encourage myself by looking for the little evidences there are, every day thereafter!
It takes me until February or March to start re-setting probably! All the events around New Year and Holidays are also disruptive 😂
I actually tend to agree with you on that ... there is a certain artificiality to them, except perhaps in this "light" ... they are perhaps attempts to prolong the joy and light of harvest, and bring hope to the New Year. Think about how much LIGHT is a part of all holiday decorations ... but by January 2, all attempts fail, and we are left with the reality of winter...