the ideology you have has nothing to do with athiesm in my opinion; i agree with nihilism to some degree by the way - but I am agnosticYou need to read beyond the title… because atheism mostly definitely leads to Existential Nihilism.
can it lead to atheism? for those who are hopeless, degenerate and dont stand on their own two - yes.
for those who have their own code, beliefs and integrity though, they will find or create their own purpose even though life and the universe as a whole itself doesnt seem to have one