Let’s just keep in mind that we have no idea who is a big Tzaddik, who is a greater Tzaddik, and who is the greatest Tzaddik of all.
To pretend otherwise is foolish and ill-advised.
Each of us does have an obligation to choose a Rav to help us find our derech in Avodas Hashem, and to advise us in observing Mitzvos correctly.
There is no obligation or need to pontificate on the merits of other Rabbanim, or on the brilliance of our own Rav’s mehalach compared to others.