Resources on how to write a totaly legal ripoff (analysis)

OK, I’m pretty much done with Star Wars because the House of the Rat continues to try and use it as a latrine. People talk about needing new intellectual properties, so here’s my thing: the law is an ass, and the legal definitions of what is derivative mean nothing to me. Too abstract. I understand the spirit of a spiritual successor versus rip off, but I need to know the bare minimum of separation before I can do more.

Back in the middle ages, fanfiction was the key to refining Arthurian Legend into an institution, but it don’t work like that now.  Can anyone point me to an analysis of ripoffs of popular franchises even games that were too distinct to be sued but close enough to be identified as a rip off in spirit? I wanna make my own Star Wars, with blackjack…and hookers! But I need real-world examples on how to do it successfully and why. Successful doesn’t mean good, successful means avoiding litigation.

Reason I ask is I’m a kind of a Ship of Theseus person, I like taking a story, figuring out what’s wrong, inconsistent, factually impossible and then take it apart bit by bit, grafting on new things until it’s a pretty goddamn different. I just gotta figure far much I gotta go. Cause at some point, it will become legal.

TBH, I already have some ideas that would radically change the tone and complexity. I want my Emperor to be WAY more like the Emperor in Robot Chicken and the “Anakin” character to have a proper father figure in the “Cleig” and younger siblings, and thus in theory a family to return to and turn to for unheeded advice. Thematic differences between magic (the Force) and religion and faith, family versus ambition, and dealing with the corruption of the Republic in a WAY more head-on way. The Palpatine is also not a relentless sadistic psychopath by nature, as much as someone being consumed by the dark side.

So basically I have the same plot as outline (thus far), but it’s thematically quite different. And could develop into something vastly different if I can figure out what I can take and what I can’t.