We likely couldnt kill a dragon with a pointy stick.
Pretty much every member of the Avengers could.
DnD PC's are not equal to real life warriors and heroes; they're literal superheroes. You can throw an 11th level unarmed and unarmoured fighter into a bear pit with half a dozen Grizzly bears, and he wins.
If he happened to be a Monk (or armed with a sword) you could toss a dozen or more in there and he wins.
Dont judge your fantasy heroes according to the standards of real life people. These are beings that from mid level onwards control epic reality altering magic, or routinely do superhuman things; consorting with Demon Lords and Gods, travelling the planes of reality, dealing with Psionic creatures, dinosaurs, undead monsters, creatures that can literally hurl blasts of flame or project forcefields and fly, teleporting, carting around artifacts of legend etc.
Yes, I think this is on point - and if you don't want to think of D&D characters as superheroes, think of them instead as mythic heroes. There are plenty of examples of heroes in myth and story besting dragons:
Gilgamesh did it;
Perseus did it;
Jason (of Jason and the Argonauts) overcame a dragon;
Bard killed Smaug
Etc.