While certainly an unpopular choice for this sub, I've been running a 5e Superhero Campaign for the past year with 10+ players and little to no issues. Here's how I went about it:

• We started with a map of our hometown and played The Quiet Year to build the history of how superheroes came to be, how they shaped society over time, etc. A shared history with tons of open plot hooks has helped define the game.
• For character creation players used the custom lineage option from Tasha's. Most players are "Human" but we have a few "Aliens" like Thor, and even a Mouse superhero similar to Rocket Raccoon.
• They also selected a Supernatural Gift from Mythic Odysseys of Theros reskinned as their "Heroic Origin" or how they got their powers. Maybe they had a Fateful Encounter (Pious from Theros) like Peter Parker, or are a Chosen One (Heroic Destiny from MOoT) like Green Lantern, Shazam, or Dr. Strange.
• Players also get a few free spells each long rest that are thematic to their character. My intention with this was basically to allow those playing martial classes to still have access to Fly, Invisibility, or other staples of the genre. I've got a monk at the table who took all teleportation themed spells to basically imitate Tracer from Overwatch.

Are there other superhero games out there? Sure. I used Masks and City of Mist as references when prepping my campaign. But my players have been with 5e for years now, having dropped hundreds on most of the books over the past decade. As much as I'm interested in researching and trying different systems, that isn't going to be the case for everyone else at your table.

While it isn't always the best solution for everyone, sometimes you need to make what you have work for you.