The admiral and yonko are on a different level than zoro and shiryu
Its not compliment like you wouldn't compare current zoro and shiryu to mihawk would you?
Kuzan luffy and bb are comparable if not stronger than zoro's eos goal
That's what I am asking, why are they on a different level? Ignore everything else for argument's sake, explain to me why you think Kuzan is on a different level from Shiryu. Don't just give me a generic Kuzan is admiral kind of answer.
Luffy already fought and defeated someone stronger than the current BB. So BB is either powering up or Luffy's gonna face a different kind of challenge against BB than Kaido. If BB power-ups and turns into a stronger opponent for Luffy than Kaido, then nothing stops Shiryu from being comparable to the current BB and Kuzan, by extension. If BB stays the same and just provides Luffy with a different kind of challenge, then we can apply some logic to Shiryu and conclude that Zoro is stronger than Shiryu, and that the fight with Shiryu is just a stepping stone to improve one specific ability—CoO to be specific.
Here is the idea, Zoro already proved himself against the most durable characters in the series. He literally has the ability that's termed the highest type of power you could wield. He's got lethality coupled with a dangerous ability. So we don't have to pave new paths in an indirect way to judge his strength. We can do this directly by comparing Zoro to the characters in question. I know as well as you do why you're deliberately going through Shiryu to make a point instead of a direct approach. It is factually easier to judge Shiryu based on Zoro than the other way around.
One more thing is, yes, I do think Shiryu is not a top-tier(For now at least), and neither is Zoro. There are certain aspects about Zoro that are preventing him from being a proper top-tier, and
power isn't one of them. Zoro, as he is now, is as much a powerhouse as any other top-tier as far as it concerns "power." Therefore, if Shiryu's not gonna be a difficult fight against Zoro "only because of invisibility," then he gotta have some broken ass abilities that make him compete with Zoro even outside invisibility.
And if Shiryu is anywhere remotely close to being capable of competing with Zoro in the power department, and if you couple that with invisibility, then he fucks up Blackbeard, Kuzan, or even Mihawk for that matter—he literally does that, period. So he is either a one-trick pony who exists to train Zoro's CoO or a proper top-tier who can freely compete with the likes of Kuzan.