It is not cope because that is literally what happened, you can see it for yourself in chapter 1009.
I dont know who is stronger between Saturn and Kizaru, there is no way to tell but I am betting on Kizaru due to Admirals being WG's most powerful unit.
Regardless of who is stronger between Saturn and Kizaru, Zoro will fight Kizaru because he was always his opponent.
I told you, Luffy isnt always beating the strongest guy around, it already happened and it will happen again, with Mihawk at least.
When Zoro fights Mihawk, there will be no stronger guy around for Luffy to beat, I can guarantee you that much.
Unlike most other people, your ranking of Zoro's power is quite accurate if we ignore the Luffy part.
Check out my thread and let me know what you think about it:
https://worstgen.alwaysdata.net/for...e-of-dreams-and-manifestation-of-power.36610/