What stories have actually interesting *Systems*?

Completely ignoring anything like story or characters and simply asking what stories have good systems? I asked myself this and quickly realized that honestly most LitRPGs I've read have really uninteresting systems.

I think Delve and Unbound have the peak of crunchy systems and smooth systems respectively, but outside of those two nothing really jumps out. So I'm a Spider So What? is the story that originally got me into the genre, and I feel like I rarely read a story with a better system than it, and it was released in 2015! The only other system that comes to mind is from Numbers Continually Going Upward, which is a parody of the genre with only 7 chapters.

Seriously, someone point me to a story where the system actually has some love put into it and doesn't just feel like an afterthought.