At best him being a challenging opponent for Brook, Franky or Jinbe is where I'd draw the line. He should be worlds below Luffy after he took down Kaido. Yonko tier being super easy to reach like SSJG/SSJB tier in Super is asstrash writing.
Still, they have no business being Yonko tier. If it were that easy to reach, there only being a handful of people who ever got so strong like WB, BM, Kaido, Shanks, Reilley, Roger makes zero sense. Two years of training isn't that much in the grand scheme of decade and decades of piracy.
How would that impact the events of BoG and onwards now that Goku isn't revived and there is no Boo or Oob (unless Goku wishes for Super Boo to be reincarnated into Oob instead to one day fight him when he once again dies).
This opens the door for people who were relevant 2 years ago like Magellan and Enel to get up to Yonko tier using off screen training as an excuse. It completely devalues G5 that it has to be used against ultimately irrelevant characters such as these, it's poor writing and makes you question...
What do you think could've happened if Gohan kept fighting on his own? Would Boo survive with the pieces of his back he released prior to the fight, or would Gohan find them and kill them?
Grades 2 and 3 seem nerfed as fuck by the CG too due to the Saiyans either achieving or coming close to SSJ mastery. Perhaps SSJ2 gets nerfed when you're more accustomed to the form as well.
SSJ3 being nerfed is a decent explanation to add onto why it's basically never used in Super.
Previous winners of the Budokais were far far stronger than Satan too, such as Akkuman. It is pointed out by the announcer that the Budokai Goku didn't participate in was boring as hell but idk how Satan's level became top tier. It's like people's memories of top tier martial artists and ki...
Also it seems that kids are emancipated from their parents at age 10 or 11 in the Pokemonverse, hence Ash and Gary being able to go out and be official trainers without parental supervision and earn money.
So perhaps the age of consent is a lot lower in the Pokemonverse compared to real life