Lmao, Oda said you can learn other things that we don't see in the manga. It's stupid to say that we should look at there and ignore the actual manga. You can learn how tall a character is, or the name some unknown DF power, it's not for replacing the actual manga story. Which is why there are contradictions sometimes, when they say Shanks was a yonko when he fought mihawk, but then the manga said otherwise, Shanks wasn't a Yonko when he fought mihawk.
In the actual manga, mihawk declined Shanks's offer to duel, twice.
It's either;
-mihawk is so powerful, he thinks Shanks is unworthy to fight, we know that's not true, this is a guy who follow people like Don Krieg and Pre-TS Luffy, and apologizes like fanboy from Shanks himself.
-Or mihawk knows Shanks > mihawk, and he simply admits the power difference just like he admitted the difference between WB and Shanks.
Shanks rivals Kaido and WB, mihawk doesn't. Understand the reality.
He respects Shanks that’s all.
Yup, they are not rivals. He fights people like Vista and Pre-TS Luffy, a level is way weaker than Yonko level. He also trains Zoro for fighting Shanks's underlings.
While Shanks rivals Kaido, stops him from from attacking WB.