I can't wait for this arc to be over. I really do like this story, the author has clearly shown they are very well versed in creating a compelling character drama, but holy shit I cannot stand this "romance" plot right now. I was fine with it at first, but it keeps dragging on. I feel like MCs infatuation with this chick is undermining his character moreso than adding to drama, which makes it difficult to read.
I agree with you in part, but I think this story is really interesting because Raviel is the one person K.D. can't redo. His skill doesn't work the same way with her, so he can't just kill himself to rewind. She will know something is different and completing the scenario perfectly will become nearly impossible.
Sure the romance is both stretched-out and really fast. A lot of that is just because they fall in love way too quickly, so if you're not that interested in shipping pretty people then this arc is getting stale.
But I really like the stakes K.D. has on this relationship. Every other relationship bends to his whims. The grandfatherly relationship with the Sword Saint (from his first failed regression on floor 21) is completely gone. The Sword Saint is just an acquaintance with mutual respect, and he's not really on the same level as K.D.
As K.D. puts it, there aren't people he can call "his own". Even the ghostly Martial Emperor isn't a guy you can hang out with freely.
But Raviel and K.D. are more of a partnership between equals. Neither can just reset and forget about the other one. To put it another way, I'm glad this arc exists even if the actual romance could've been handled better.