While I think Lüxia was a bit much this time, well, the dude was not nice either. He only got attached to transmigrated Lüxia because of the typical shoujo manga trope where the high and mighty male lead goes: "oh you dare to talk smack back at this great me? I'm suddenly interested in you now"
If you guys go back to the first chapter, Mingzhe didn't just reject the original Lüxia but also mocked her. When he saw Xiaozhen bully Lüxia, he purposely ignored it and said something like "I don't care about insignificant person like that". And then when she calls him he said "You think I like you? Just go ahead and die, don't need to put a show". That's what agent Lüxia meant when she said it would be different if he rejects her properly. If he doesn't like real-Lüxia, he shoukd've made it clear to her, not mock her.
And its just decency as a human being that if someone is about to commit suicide, you should call for help or stop them. Not tell them to just die.
My issue with how Lüxia did things here is in this case the erasure of her existence is so confusing. Like, nobody remembers that she existed at all, but did she also erase all memeories of everythong that transpired? Min's sister was saved by someone, so if Lüxia doesn't exist, then who did that? Also as I said in last chapter's comments, what about Lüxia's parents? Did her parents also cease to exist too? Did they forget they ever had a daughter? Are they still just obliviously travelling around the world without remembering where the money came from?
She calls him bad for ditching his family for the sake of some infatuation, but if she just left the Su parents hanging about their daughter's fate, then it's shitty too?????