Let's discuss some of our favourite dramas here the ML is either the villain, or is a second lead (i.e. FL likes another ML first) who ends up getting the girl! Some of my personal favourites:
I love that you mentioned Love Better Than Immortality! It is one of my favorite dramas with my two favorite Chinese actors (Lu Si and Hong Yi) as the leads, along with my favorite theme, time travel! This drama was perfect in every way for me, I was watching it while it was airing (I can't believe it has already been a year!) and I never got bored aha. I'm still waiting for a drama that can fill the hole the LBTI left in my heart :(
I don't know any other dramas with a theme like that unfortunately :( But I hope that some can get created, most evil characters in dramas weren't evil from the beginning and just want love/attention from someone! Dramas with these types of SML have left me having second lead syndrome many times, if only they could have their happy endings :(