Theirs has been a turbulent relationship for a long while, predating their arrival to Verens. Guzma's respect for the man has grown, and so too his attachment.
To say they don't understand each other is a disservice. You could not find two more different people if you tried—like oil and water they hold similar miscibility.
Both are failed leaders who find comfort in one another. Whether that be through drinking or fighting—sometimes both! It helps them bond, oddly enough.
A smug punk that Guzma sees a younger version of himself in. He doesn't care for him much. Whether because of this or in spite of it has yet to be decided.