While I was also annoyed at first by minato he's a kid. Even if you were to compare him to shizuku saying that "well shizuku was well behaved as a kid" you need to remember not every kid is the same shizuku grew up in an environment where she had to act mature as to not burden her mom and compared to her minato has more room to act childish as he grew up with 2 parents who could give him lots of love and attention. Shizuku already had her "story arc" where she learns to be a bit more spoiled and open with her parents and I'm pretty sure minato and eventually the 3rd kid will get the same kind of character development too
While I was also annoyed at first by minato he's a kid. Even if you were to compare him to shizuku saying that "well shizuku was well behaved as a kid" you need to remember not every kid is the same shizuku grew up in an environment where she had to act mature as to not burden her mom and compared to her minato has more room to act childish as he grew up with 2 parents who could give him lots of love and attention. Shizuku already had her "story arc" where she learns to be a bit more spoiled and open with her parents and I'm pretty sure minato and eventually the 3rd kid will get the same kind of character development too