I decorate for the seasons.
I kick off winter with a fondue party and make my place more “hygge” for the season. Candles, cozy blankets, baking bread, making tea and soup. Decor involves pinecones and coniferous branches, my rustic dark wood table is left uncovered. I have smart bulbs, so usually warm lighting. That sort of thing.
As a contrast, in summer I go more Mediterranean accents. Bowls of fruit, a wreath of wildflowers, I make limoncello and instead of candles, I’ll use an Aera scent machine for smells like “fresh laundry.” I frequently have bouquets of lavender around, and a French country tablecloth on the rustic table.
That’s the general idea anyway. Fall might have gourds, leaves, and cider in the mix.
So, while not really for a particular “holiday,” I do enjoy honoring the seasons by trying to be in sync with them. I live alone, but entertain quite a bit.
You may want to familiarize yourself with the philosophy of Stoicism. It sounds very similar to what you describe. I’d recommend starting with a “sampler” like “The Daily Stoic,” by Ryan Holiday. Epictetus and Marcus Auralius are two of the biggest names in terms of “fathers” of this philosophy.
Don’t go by whatever impression Hollywood or society may have left you with about the word “stoic.” It doesn’t mean “without emotion.”