Mate Mourinho has had three bad months which doesn't negate more than a decade of success which is 10x more than what Klopp has achieved till this point. Even Van Gaal has achieved far more than Klopp although it can be argued that his golden years were some way back
Some might reasonably argue that Wenger merits a discussion as well as you yourself concede
Either way it's extremely premature to call Klopp the best manager in the league considering he won one EPL game against a Chelsea side undergoing the worst start to a season in decades
Silly argument to compare them. We will never know unless Klopp goes to Real Madrid or Barca and we can see if his time there would be a failure as well.