In my campaign low level magic is pretty ubiquitous, but my current campaign is relatively low level magic for what they have. I think each PC has 1 uncommon magic item, one of them may have 2. They're 8th level. In addition, I regularly throw 5-10 encounters between long rests.
Powerful? Yes. Superheroes along the lines of Thor, Superman, The Hulk or The Flash*? No. More street-level fighters. Then again, they aren't facing down Doomsday, Thanos or other galactic threats either.
But in another campaign they could be glowing with all the magic they have and facing down Tharizdun.
While D&D doesn't exactly fit the "gritty" checklist, it doesn't have to fit the upper tiers of superhero checklist either. Which is awesome. Give that paladin a cape of flying, armor of invulnerability and girdle of storm giant strength along with a holy avenger if you want. Won't happen in my game, but everybody has a preferred style of play.
*Depending on version of course. There's incredible power differences between powers of even individual superheroes.