Hey bro i'll answer ur question here, though we know too little of both, i think that Katakuri guy resembles Akainu, even if he's being attacked by Bege and Jinbei he just ignored their presence and went straight after Luffy and grabbed him instantly, Jinbei attacked him from behind and nothing happened. Also notice how he's dangerously smart and persistant, he doesn't play around. He is for sure the smartest 'Charlotte'.
Having said that Marco us also strong, and that he was (one of the) strongest whitebeard pirate says alot. But he couldn't damage Akainu and Kizaru. I think they're around the same lvl and Marco also survived the war after fighting Akainu and Kizaru and he kept going on.
If i should put Katakuri against Akainu, i can see him putting up a good fight and maybe after the time-skip Marco would also. But for now (if i forget about plot reasons) i'd say Katakuri though it's hard to imagine Marco losing