Batman and Superman's climactic battle in the film takes place on a dreary night in Gotham, Superman being poisoned with Kryptonite for the first time while overlooking the city's gritty industrial landscape.

Source: https://screenrant.com/batman-v-superman-dawn-of-justice-hidden-details/

Being trapped with a chunk of Kryptonite for 30 years damaged her brain, making her prone to wild mood swings.

Source: https://screenrant.com/marvel-vs-dc-most-powerful-superheroes-ranked/

John Clark is an online-homeschool course developer for Seton Home Study School, a speechwriter, and the author of two books, How to Be a Superman Dad in a Kryptonite World, Even When You Can’t Afford A Decent Cape.

Source: https://www.ncregister.com/blog/will-christmas-be-transferred-to-sundays

Unless Two-Face gets a bunch of Lex Luthor's Kryptonite weapons, he should never battle Supergirl.

Source: https://www.cbr.com/dc-villains-should-never-fight-supergirl/