FWIW it has at least passed a sniff-test from Bellingcat, which is probably as close as us normal mortals will ever come to being able to vet a doc like this. If Bellingcat FSB sources suggest this was 'probably written by a colleague' then it at least moves from /r/warcollege fanfic and into the realm of potentially legit.
A KGB guy just set out to write a rand that demoralizes the russians and gives hope to the ukrainians?
I'm all on the side of the ukrainians, but I'm 99% sure the document is not real.