Madara's regular Susanoo cutting only two mountain tops will always be inferior to Kurama Susanoo cutting at least six.
No it won't. The only scenario in which it would make sense was, if you stacked 6 mountains behind one another, with Susanoo only being able to bypass two, while Kurama-Susanoo would be able to bypass six, but as I said, in the fight with Hashirama, the only difference was Susanoo swinging its blade with a larger range of motion, nothing more. I also love how you say "tip of a mountain", as if that slash would not have gone through the entire one. We can see in the manga how the shockwave keeps traveling through the landscape after cutting the mountains, which means that cutting those tops didn't stop the attack.
And also, as I said, against the Kage, the swing of the perfect Susanoo's sword was even mitigated by the large meteor in its path which Susanoo had to burst in the process, so it wasn't just a comparison of "two mountains vs six mountains".
This is comically superior to cutting a few mountain tops
Another comically superior
This is also superior
This too
Comparable if not superior
Luffy being able to punch through an island is also far superior
Pre-timeskip Franky surviving this explosion, which again, is far superior to cutting a few mountain tops
So even though I already said that for the most part, Naruto has better visual feats, One Piece still has ones comparable to or far superior than Madara's multi-mountain top slice.
Mostly not comparable.
Whitebeard tilting the island: not a direct AP feat.
Aokiji freezing the ocean: not a direct AP feat.
Law cutting the mountain: hax, not raw strength, and Madara's range was larger, as it travelled through a mountain range, while Law cut the mountain he was standing inside of (which means the radius of Law's blade was effectively half the mountain).
Garp: nothing was said about "warm up" or how much effort Garp needed. He had to specifically prepare himself by crushing those mountains. Even if Garp crushed a mountain with one punch, Madara can slice through a mountain range.
Chinjao splitting a "continent" obviously too is an exaggeration. Sai already replicated that feat as per Chinjao's own words by splitting a hill.
That being said, yes, high end moves of highly destructive characters can do massive destruction too. But it's not something characters can casually replicate.
Fujitora has no such limit, you're confusing "yet to have done it" with "being unable to do it", Fujitora has already demonstrated both the range (through pulling meteors out of space), and strength of gravity (through lifting the rubble of Dressrosa) to achieve such a thing, Madara is getting flinged into orbit with or without his Susanoo.
So what stops Fujitora to just fling all other admirals or Yonko into the space? There is an obvious restriction made by Oda and so I won't entertain fictional feats.