2 things about that.
1. What's his chain? How is he higher? I legit don't know
Zoan Drake drew blood from Guernica twice and fought a good fight against him offscreen (as stated by Guernica himself), and Guernica not only took the Yonko-level Boom better than Luffy did, but tanked the Kazenbo (which hurt the Yonko-level base Yamato) with little to no damage, and survived a blow from a
pissed Shuron Hakke + Haoshoku Infusion (as there was purple lightning when Kaido struck him) + Hybrid Kaido and with enough left energy left in him to take photos of Gear 5 and send them to the WG.
In short, Zoan Drake held his own against and drew blood from someone who at the very least is base yonko level in both durability and AP (as he pierced Drake's own yonko-level durability which offscreen took sound attacks from Apoo which scale to Base Luffy's Yonko lvl durability).
Meanwhile, Sulong Neko and Inu could only do minor damage to Dragon Kaido and were easily overpowered by a serious Base Kaido when they did a combined attack, and keep in mind they stomped Jack in those same Sulong forms (and later when Inu fought Jack on his own, his Sulong form stomped Hybrid Jack).
So basically:
Hybrid Drake is somewhat weaker than Base Yonko level in AP, but is definitely comparable and can hold his own (and due to taking Apoo's sound attacks is more durable than Base Post-Udon Luffy who took hits from the Yonko).
Also, you could definitely argue that, while Buso Zoro was not serious against Apoo until he one-shot him with Shishi Sonson (meaning Hybrid Drake does not scale to Full Power Buso Zoro), he did put in more effort against Apoo than he did when he effortlessly blocked the Kaifu with 1 busoshoku sword (seriously, both the manga and anime show Zoro effortlessly smacking that Kaifu away casually with his sword, and compare that to casual Zoro struggling with Apoo, who Hybrid Drake scales to).
So Hybrid Drake probably scales above Kiku, who is equal to Jack.
Zoan/Hybrid Jack got demolished by 2 people who are well below base Yonko level, and even got stomped by one of those people again in their rematch once Inu went Sulong.
2. Stomped-? Didn't two of them jump him and still got stalemated for days, then in onigashima beat him only after a whole nation of sulongs took a crack at him?
That was Neko and Inu's base forms.
When they went Sulong form, Zoan Jack
got beaten to a pulp and would've died had Kaido not stepped in.