Basically Kamala's ancestors came from another dimension. And those bracelets were part of a tool to open a portal to that dimension/universe. But by opening it... a recursion would happen destroying earth.
At the end of the final episode, it's discovered that her genes were mutated and that the bracelets weren't the source of her powers....
So yeah, they teased it. But like everything else Marvel's been doing lately, there wasn't any follow up. Clearly, though, mutants aren't going to originate on the currently MCU timeline/universe.
The only other way they could've introduced mutants is by using the infinity stones. After the 2nd or 3rd snap, it activated the mutant gene. But they used as in Eternals, and it still wouldn't have made sense.
I'm sure they've pondered what to do since 2020. In order to things the right way, they would need 2 to 3 phases of mutants.. then a cross over. But they can't really do that because they got other IP's with arcs that have either just started or are not finished. And I'm sure Marvel doesn't want to shoe horn in their crown jewel IP's. if they fukk them up, there probably isn't no coming back. Yeah, they can afford to fukk up Ant-Man or The Marvels, but they didn't pay billions to get the rights to those movies.
You can intro Mutants in 1.5 phases imo.
3-4 movies in a year + 2-3 shows way more than enough the the end phase movie being X-Men or X-Men vs Avengers.