A larger Bismarck force would multiply British commitments

Would adding more ships to Bismarck's sortie simply have caused Germany to lose a larger force?

Possibly, but the larger sortie would first force Britain to concentrate more ships in several hunting groups and weaken convoy protection elsewhere.

A stronger German force would not automatically win the resulting battle. The British response is the important part: King George V, Prince of Wales, Hood, Victorious, cruisers, and destroyers would need to operate in larger combinations. Britain would require at least two or three groups to cover different routes and prevent the Germans from simply evading one pursuer. Destroyers and other escorts taken for that search would no longer protect convoys. The Germans could also divide after entering the Atlantic, expanding the search problem again. A fleet creates strategic value by compelling costly precautions even before combat begins.