Any time anyone looks at Judd or Grace wrong you know the other one is gonna say something. Every time. They don’t care who it is, they won't let it slide EVER.
The end for Minato is learning that he has to trust his feelings and not worry only about other people but also worry about himself. That he has a right to be both selfish and selfless at the same time, that his love is worthy of being love and that his worry is worthy of being a worry.
His isn't a journey of maturity but of self-acceptance, of realizing that he can be himself, bad adult and all, and still love and be loved and be worthy of that love from another person who he feels is so much better than he is.
Minato learned that he mattered as himself, that his authentic kindness and love and gentleness all mattered and deserved to be loved in return.
He didn't have to become the more mature one, didn't have to be the one with a better handle on everything. He just had to be the one that Shin loved.