Seems the latest update of Big Sur 11.2.1 a few days ago broke SS (and all its own screen savers as well) on my Macbook Air M1. Perhaps.. due to some command line code that prevented random screen savers coming on that one could not escape from.
So, is anyone else finding the SS no longer comes on with the time function? It previews just fine.. just won't start on its own.
EDIT: so that was yesterday, today it seem to work just fine.