Karl Lowith has a book called Meaning in History, which explains how all the various 19th and 20th century ideologies looking for meaning in history are copying tropes from Christian theology. He has a wonderful line in that book that your remarks reminded me of. He says, "mankind cannot be saved because mankind does not exist".
He explains - mankind is an abstraction. Human individuals exist. To look for salvation in history is to look in the wrong place for what will never be found there. It is an individual, not a collective, matter.
FWIW...