Last year I humorously told my 7yo kid that Santa Claus died of COVID. Already before COVID though, we had the Christmas tradition of watching Futurama's "Xmas Story" episode, pretending that Santa has been replaced by a murderous robot who kills people during Christmas day.

It's all a matter of perspective. In our case, we've replaced mythology with humor and subversion - I prefer the latter to the former, and the kid fully embraced it (making the Futurama episode our tradition is their idea) :)