Those Who Aspired to Become Gods : A darker fairy tale One of RRL's novel but its not a fanfic its original story. Ancestor, Wake Up! RRL, Mc have a clan.
Most of Andur's stories on RRL have a good chunk of kingdom/faction building(including good old world domination). Starting with "Untill Death?" https://royalroadl.com/fictions/search?author=Andur https://royalroadl.com/fiction/10301/apex-predator is also a mix of WD and faction building. There's actually quite a few of those if ya look around.
I think there was a Qidian novel that was a total rip-off of the Fallout series. I forgot its title though.