Oh wow, the demonic scythe trope is like catnip for a certain kind of dark fantasy lover. The most immediate one that comes to mind is 'Soul Eater', where Death the Kid's dual pistols are technically demon guns, but the whole series is dripping with scythe-wielding Meisters—Maka Albarn's weapon partner Soul Eater Evans transforms into one. It's not explicitly 'cursed' in the traditional damned sense, but it's a weapon that consumes souls, which scratches a similar itch.
Then there's the webcomic 'Kubera', though it's more of a slow-burn mystery. One of the primeval gods, Kali, is associated with a scythe, and it's deeply tied to concepts of destruction and fate. It feels more like a relic of cosmic horror than a simple cursed item you'd find in a dungeon. I've also seen it pop up in a ton of web novels, especially the ones with regressor or system leads; the MC often finds a 'Cursed Scythe of the Abyss' or something similar in a hidden dungeon, and it usually comes with a nasty side effect like draining lifespan or amplifying negative emotions.