I'm wondering if their awakening cancels eachother out and does nothing to the environment, or makes a jumbles mess of Mochi-String. Either way, I don't see it being a determinant factor.
Katakuri's Kenbunshoku Haki is superior, but there's always the possibility that Doflamingo's can develop throughout an intense fight since a less experienced Haki wielder (Luffy) could do so. Busoshoku is up in the air as both are seen superior to Base Luffy by a massive degree, easily breaking his guard several times. Haoshoku goes to Doflamingo for a superior display in control and usage in conjunction with his physical strikes and busoshoku.
Doflamingo's got the stamina advantage. Katakuri's Body Control would allow him to subtly dodge attacks more easily, but Doflamingo has cloning, flight, and Parasito (assuming it works properly. Even if Katakuri can remove it via body control, all Doffy needs is a moment to get a decent hit in).
Katakuri's Regenerationn is useless if he is struck by Haki, which Doflamingo can apply to his DF and body with ease.
Doflamingo's threads are also hard to see individually, as shown when he very casually caught Smoker, Sanji, and Law by surprise. And yes, Katakuri is susceptible to this--he didn't notice Flambe's silent needle.
Overall, Katakuri is superior on the offense, but Doflamingo is superior on the defense, and he's got incredible endurance compared to Katakuri, who began flagging from a stab-wound to his side whereas Doflamingo got through all of his organs (presumably) exploding. Doflamingo's got more variety and range as well.
Doflamingo High-diffs Katakuri. Either way, Luffy would have never defeated either of them without outside assistance... (Katakuri weakening himself and fighting Luffy honorably post-Flambe, and Doflamingo having to muscle through half-assed healing from injuries that would have killed him in minutes, and fighting off all of the Coliseum fighters)
