Exactly why TOS was, and still is, more interesting than TNG ever will be. TOs was aspirational. "We ain't perfect (yet) - but we're trying real hard" is a more entertaining through-line than "we've solved all our problems back on Earth and we're here to solve yours".
True. TOS, exemplified in episodes like "A Taste of Armageddon", has Kirk admitting to Anan7 humans are killers... "but not
today". Shatner pretty much ensured he was perfectly cast as Kirk for that scene alone. It's one of Trek's better stories, where the plot may be superficial and constrained but the set pieces that tie into it are of so much greater value.
TNG feels like evolution from TOS when humanity did finally get close to that point. After all, if humans didn't evolve from cavemen times, imagine how much worse it would be. Or better, it depends on what frame and mind and contexts you're wanting to consider at the time.
But TOS also did the "We're here to solve yours", as "Errand of Mercy" is very quick to demonstrate and in a way more than what feels like 90% of all TOS in general where Kirk or other major character either says how computers turn people into automations, or - far more dramatic - makes the computer go all splodey cuz' computers should not be doing humans' work for them - just what sort of acid were they all doping in the 1960s anyhow?

Episodes involving such anti-computer sentiment - aka "compuphobia" - include but may not be limited to: "Return of the Archons", "The Apple", "The Ultimate Computer", "I, Mudd", "The Changeling", 1979 TMP, "A Taste of Armageddon", "The Conscience of the King", etc...