Its ok buddy. Oda is making it clear that lava fire. Kaido just isn't up to par
No one cares if magma is hotter than magma at this point. Anyone uses fire based attack and you are like "mAgMa iS hoTtEr".
If Kaido was ONLY able to use fire based attacks then maybe but even Kaido said last chapter. Only HAKI is important.
So while you are crying about Kaido's amazing feats and trying to compare it with the Akainu's fruit. I will enjoy the show.
Edit: i maybe a little bit too offensive on my post. Sorry about that.