A British supercarrier would answer British strategic needs

Could the Royal Navy have built a better supercarrier than the Forrestal class with enough money?

It could build a carrier better suited to British needs, but not an objectively better ship for every navy and strategic setting.

The Midway and Malta concepts were national solutions to the same armored fleet-carrier problem. American designs favored somewhat larger air groups and the maneuver room of the Atlantic and Pacific. British designs accepted more protection because regular operations near hostile land-based aviation in the Mediterranean and Southeast Asia shaped their requirements. A British supercarrier could therefore be better for Royal Navy needs without being universally superior to Forrestal.