I will die on this hill. The reason you feel so gloomy/no longer nostalgic during the Winter Holidays(New years, Christmas, Yule, ect) is because you are trying to bring it up too early. You start watching movies November 1st and jump immediately into decorating. You watch cozy tiktok compilations. You rip the joy out of actually building up anticipation. Letting Halloween simmer for a bit longer. Slowly move into larger family gatherings and cozy feasts. Then, decorating once nights feel imposing, using holiday lights strung around your house to brighten it. Putting up a tree in December, when the vibes are just beginning. When you start to see every other store get into the mood.
You rush yourself for the desperate need to feel something nostalgic. You refuse to let yourself be in the moment. To let a day pass where you aren't constantly looking forward to it. It is the reason you don't feel that much happiness. You're getting a dopamine hit for every movie, but by the time everyone else is starting to decorate, this has become obsolete to you. Your brain requires different stimuli now.