What counter does he have for the sharingan ?
Sharingan in what? As I have said in another thread, FS itself doesn't give you immunity against strong genjutsus but Katakuri can easily predict such moves. Note that CoO users can literally fight totally blind which makes eye-to-eye genjutsus almost useless.
Apart from that, let's compare them (I'll take OBD stats as a comparison):
AP/DC:
The Naruto characters Pre-War arc are not comparable at all to Katakuri, the exceptions are Itachi and Nagato. Hence Katakuri conformably beats everyone else with a few powerful hits.
Durability:
Katakuri takes it conformably as well but like I said before, Itachi and Nagato are an exception here (especially with Susanoo). But the rest of them are no real competition.
Range:
Katakuri can cover entire areas (several hundreds meters) into his awakening, hence he has both long ranged and CQC attacks via awakening. Deidara can compete with his strongest bombs but outside of him, Nagato has to pull out his strongest attacks to reach similar AOE - with huge drawbacks.
Speed:
Katakuri has relativistic with light speed reactions; far superior to the Akatsuki members, even Itachi and Nagato are slower than him.
Furthermore, due to Katakuri's CoO, his precognition allows him to see several seconds into the future, allowing him to see entire moments whatsover his opponents are doing.
Hax:
Due to Katakuri's logia-like body, he also has some sort of intangibility in which his opponents cannot deal real damage against him as long as they do not have something which is effective against mochi.
However, Nagato and Itachi have sealing techniques in which they could defeat Katakuri with a single hit; Itachi with his Totsuga Sword (note that Katakuri can take off body parts to save himself from that sealing technique just like Killerbee took off a part of his body when Amaterasu hit him) and Nagato with his soul manipulation.
Also, Deidara shouldn't be underestimated either since his stronger bombs are very powerful - C4 can destroy Katakuri's cells with microscopic bombs but I guess, as long as Katakuri uses effectively his shape-shifting ability or takes off a part of his body, it shouldn't be that effective.
All in all, Katakuri beats all Akatsuki members but he stops at Edo Madara; dude is just too powerful for him.