The old man in red and white bearing gifts comes from folklore and that’s the part I love.
I did the same as you and commercialism got my girls writing their letters to Santa. Unfortunately, their list was long and the requests expensive so I bought a nice selection from it. But because they didn’t get everything they asked for, they were still disappointed and confused. They discussed it between themselves and decided that Santa didn’t exist and that it was actually parents who bought the gifts. And suddenly they became much happier with the gifts they had because they understood I didn’t have the money to buy them everything they asked for. They were 4 and 7 at the time.