Like think about what we know about Smaug from the bulk of Tolkien's work. Dragons were far more common in a prior age. Sauron and Morgoth bred them. Smaug is not the most renowned dragon (that's Ancalagon the Black) but he is noteworthy in that he's pretty much the only dragon we know that survived
And the way he did so is by being a pretty damn smart dragon. He's got a lair you don't really have any hope of penetrating without significant help (the One Ring, no less). He's girded himself against the typical vulnerabilities of dragonkind. Literally armored himself with gold and jewels.
The way he was beaten involved using one of the rarest treasures in the setting to infiltrate the lair, playing head games with the dragon to bait him out of his lair, and then BARELY managing to get word to one of the best archers of the age about a very hard to spot weakness. That's not nothing.
In fact, that's got all the makings of a pretty good adventure. You tell stories about that for years.