Lovesick
A role-reversal enemies-to-lovers superhero gay romance, where the hero isn't being so nice, his nemesis isn't all bad, and nothing goes as planned. Warnings for a deep-dive into bipolar depression, emotional manipulation, dips into dubious consent, and comic book level violence.
Detective Danny Grant, the superhero Elemental called Zeus, is coping with trauma and not handling it well. The past year before the series begins saw him lose his partner to the terrifying Elemental, Thanatos, come into his own powers, and then just when he thought he had a handle on things and asked for help defeating Thanatos from the less brutal Elemental, Malcolm Cho - Cho never showed, resulting in even more death, including Danny's mother. Thanatos was defeated, but the toll was too much.
A chance encounter with Cho now months later gives Danny the chance for the sweetest of revenge and an outlet for his anger and depression - to seduce Cho, get him to fall in love with him, and then break his heart to spite him. Danny falling in love himself, facing a new villain, and finally dealing with his past, his trauma, and what he wants of his future is a long and winding road in this complete two-book series.