How does the Worm Universe compare to Marvel's or DC's?
The first thing to keep in mind, is that Worm is the result of a single story. The tale of Taylor Herbert.
In order to tell that story, Wildbow created a hugely detailed universe and populated it with dozens of extremely fleshed out characters, each having their own distinct personalities and agency. Those side characters are given the chance to present their own perspective, but the vast majority of the story is seen through Taylor's eyes.
That means that the Worm Universe (Wormverse?) is consistent, self contained and more "realistic". Consequences are real. When a character dies, they stay dead. Disasters are not erased from an issue to the next. Changes in personality are not retconned. The characters have to grapple with the consequences of their actions and those of their enemies. When a city in the story is torn asunder, the book focuses entire volumes in how they deal with the fallout.
DC and Marvel, on the other hand, don't show a consistent universe. Theirs is a collection (a vast one) of tales from hundreds of authors, about different aspects of a hero's life. Those heroes evolve and change as time passes, sometimes switching tracks and sometimes staying consistent. But the sheer scale of the assorted stories makes the creating of a single "universe" impossible. How many reboots have occurred? How many times a character died and was revived?
DC and Marvel show instead something else, a panthenon of greater-than-life heroes, whose personality and deeds transcend the design of a single author, and are the result of the combined effort of decades-worth of stories and tales. They are the Greek gods of our time, and the universe is secondary to the characters.
It's not exactly a fair comparison, both things are too different from one an other. A closer comparison would be one between the universe of the Watchmen and that of Worm.
But that would be a whole other question.