Criminally overlooked is the Korean webtoon: webtoon character na Kang lim. In my humble opinion it's one of the best harem stories within the medium. It mixes Steins;Gate's time leap with re:zero's return by death.
A normal guy gets pulled into his favorite webtoon's deadly storyline and has to relive events again and again to save the main heroines, slowly turning from a bystander into the story's true main character.
The cool part is that all the usual anime/manga/webtoon clichés actually make sense, because the webtoon world is literally merging with reality, so those tropes become reality and work really well for that sole reason.
For example the dude saves a girl from the Yakuza at some point (not even the craziest thing he does btw). Also, I wanna mention is his best friend's arc towards the end is literally peak fiction. My criticism is that the story doesn't deep dive into all the mental struggle the dude had to go through after all those loops, something that would have been pretty neat.
It might not be the best story or webtoon in the world but it is nonetheless amazing and it deserves a chance!