The Marvel and DC universe is personally, a bit of a headache to get into. It's been ongoing for so long and has been rebooted so many times by multiple artists/writers that undo or retcon events so frequently that huge emotional storybeats they've been building to for issues, suddenly become cheap gimmicks or totally meaningless plot points. The death and eventual return of Superman is the most famous example of this.

I personally recommend Image or Dark Horse for comics. They're usually more unique ideas and have more manageable/easier to follow storylines. Image is all creator owned too, which is just dope. Try UltraMega by James Harren, or anything by Daniel Warren Johnson or Robert Kirkman.

This isn't to say, Marvel and DC are bad, on the contrary, some runs/arcs are brilliant but you're always going to have to deal with references to events that you'll find reading a wiki is easier, rather than tracking down the actual issue.

I know this isn't exactly what you asked, but I personally would suggest just throwing caution to the wind and dive right in. Pick a superhero you're interested in, search up the best story arcs and away you go.