Could a fleet carrier have changed Denmark Strait?

If Lexington or Saratoga replaced the British carrier near Denmark Strait, could its air group sink Bismarck without battleship support?

Yes, with a full air group. Victorious's limited, incompletely worked-up aircraft force and the weather made her actual circumstances quite different.

Lexington or Saratoga with a full air group could sink Bismarck without battleship support in this counterfactual. The question first needs a geographical correction: Victorious was near Denmark Strait, while Ark Royal was with Force H and approached later from the Gibraltar area. Victorious had only a small Swordfish force and a half-strength Fulmar squadron aboard while preparing for work-up. Keeping the Swordfish available for a strike pushed scouting onto Fulmar crews who had not trained for it. Poor weather added to those limitations.