Which to me is an unfair expectation.
We knew this was going to be a Superman debut and the beginning... with the expectation of more to come. That excludes Kingdom Come, Action 775, and All-Star from the running immediately, which all feature seasoned veteran Supermen... heck, two of them are "end-of-life" Superman stories that get away with kicking over sacred cows and throwing in kitchen sink, because it's meant to be a final, terminal ending.
"Secret Identity" is a meta-textual Superboy story... MoS could not have the benefit of that 4th Wall aspect of Superman pre-existing in his own universe. They also wanted the debut of an adult Superman rather than a redux of Smallville or the weird time-skip-in-a-cave from the Donner films. However, the meat of the adult story is that "first-contact" interaction between the first fantastic and the government (going from begrudging mutual alliance to eventual friendship). MoS captured that... Clark was just as "playful" in the interrogation and in confronting the General... dropping a drone is a little less terrifying that reorganizing the US nuclear arsenal... it's also a more reasonable power-scale that you can use for future films (a Supes that can effortlessly swap nukes is a little too strong for modern rational film).
Birthright and Earth One were likely amongst the strongest influences on the film, even if they're diametrically opposed with respect to how one arrives at the responsibility of the cape and crest. Earth One is also more of a Superboy-ish story (where Clark is an entitled man-child entering Metropolis lamenting his options in life) whereas Birthright accounts for the "lost years" between high school and Metropolis. MoS likewise accounts for that time but with Krypton as Clark's watershed moment, rather than an intricate political and civil war in Africa (great reading but awkward to translate to screen without other unnecessary implications). The main thing I missed from Birthright was MoS lack of color on Krypton which would have so easily explained and justified- as it did in the book- Superman's color scheme... many forms of costume and dress instantly make sense when ascribed to someone's heritage and culture.
I'm not saying those aren't great works, but I think your expectations- like many viewers- were unfair... expecting a seasoned paragon father-figure out of the gate wasn't the intention nor should it have been.