I also live alone and i dont line up culturally with my family much and dont really do holidays. I do like changing things up a bit in different seasons but its not holiday related. Like for example switching out a few fridge magnets between Summer, Fall, Spring, Winter themed stuff. Id do more but it costs money i dont have.
oh and i will change background images on devices to match the season. Like my phone has a spooky forest and orange theme right now.