Anyone can fight for days. What matters is the level of competition.
Marco is stronger, faster, tankier (like unbelievably tankier), and probably more intelligent than Katakuri.
Again, I think Katakuri beats him 1v1 because Katakuri can seal Marco with his awakening, but that's that specific matchup.
If I were going up against someone like say Kaido, Big Mom, Mihawk, Akainu, etc., and I had to choose between having Katakuri on my side or having Marco, I would choose Marco.
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Marco literally had like half his fucking head blown off by Kizaru and he regened like immediately.