Something like in Can I Connect to Your Wifi? ML and MC knows each other as neighbors but unknowingly also as artist and fan In After My Ex-Boyfriend’s White Moonlight Proposed to Me they get close as strangers without knowing each other's names and reputation Or being close online not knowing that they know each other irl Or cases of hidden identities. Also something along that vein, Someone tries to matchmake the two and they refuse but turns out it was someone they already like The logic around these kinds of story is often questionable but I'm taking any rec!
Earth is Online? The MC and the ML know each other online but never met up. They get caught in an apocalypse trying to find the other.
He Lifted My Red Veil , it's about an online game and both the ml and mc have two accounts global university entrance exam as well could work.
Guide on how to fail at online dating Don't discriminate against species(its a slowburn but MC and ML knew each other before and forgot) Don't pick up boyfriends from a trash bin(QT) Holding Onto My Man(QT) Rebirth of a cannon fodder from a novel(MC and ML knew each other in previous lives but forgot)