How to justify superpowers in a story ?

I am starting a superhero story. My problem is : where does the powers would come from ?

I originally thought about superheroes being created in laboratories, but it’s not original and overused (super-soldier serum, compound-V)
Same with a gene which gives powers, like in MHA or Xmen.

Do you have any ideas to avoid/modify the usual tropes ? I already asked another sub, but I would like advices from superheroes fans.