OMG YES I GOT ONE FOR YOU
https://www.mangago.me/read-manga/beyond_memories/
i feel chinese manhuas are kinda big on that cuz i remember reading a lot thats like uke chases seme but seme only dating uke as a substitution for his white moonlight and after they "die" they regret it but like the chasing arc is not as much there bc it usually starts w them being "together" already like
https://www.mangago.me/read-manga/the_substitute_relationship/
or
https://www.mangago.me/read-manga/black_lotus/
and then theres also this which is kinda similar but uke and seme are together in the beginning until seme gets amnesia and uke tries to rekindle his feelings but seme hates it and its not until uke stops chasing that seme regrets it
https://www.mangago.me/read-manga/peppermint_candy/
these are the ones that were off the top of my head so far (づ￣ ³￣)づ
Mannnn i really want a manhua hwa or manga where the uke loves the seme and chases after him, but the seme finds it annoying and doesnt gaf about the uke , the the uke gets injured or dies and seme regrets it.