Flamestrike
Legend
I think a lot of this is because of the wonders of movie-making and the difference between a film and a game, which have different effects.
But compare Superman and Batman without gadgetry (or naked, lol). There's no world in which Batman wins. Ever. The only way he wins is through tech and/or trickery. Furthermore, Superman could theoretically learn to use all of Batman's toys, but Batman couldn't learn Superman's powers.
Hawkeye is Thor's "equal" as an Avenger and fellow combatant, and is capable tricks that makes it so he can do things that Thor cannot, but there's really no world in which Hawkeye defeats Thor in a one-on-one contrast. Or rather, Thor wins 99 out of 100 times. The only way Hawkeye could win would be through use of an arrow to collapse a mountain on Thor, or some such.
On the other hand, it may also be that there's simply more "swinginess" in the MCU. In MCU, you could stab Doctor Strange with a fork and he's dead; that isn't possible in D&D, at least vs. high level characters. On the other hand, MCU has its own brand of ridiculousness - like Tony Stark somehow surviving immense falls in his suit.
The point being, both are different brands of very fictional action, and go by different laws. In my post above, I offered an ad hoc approach that I might take, but there are other ways to do it. I mean, everyone could theoretically be capped at 10 or fewer levels, but but augmented heroes have extra stuff layered on. I mean, Hawkeye is a far more skilled combatant than the Hulk - he's about as good as you can get without augmentation - but would be slaughtered. So maybe you have Hawkeye as a 10th level fighter (or ranger) with normal stats--good, but not superhuman--and the Hulk as 3rd level, but 30 STR and 30 CON, damage resistance, more HP, etc. Or something like that.
Batman has beaten Superman nearly every time they've fought.
Superman put his XP into strength, speed and flight and near indestructibility (DPR and HP). Batman put his XP into skills and gadgets and feats that let him have a say over the plot.
In a supers game like Champions both would have the same number of build points and be on the same power level.