What if every R-class battleship had been modernized?

How would the war change if every R-class battleship were refitted to Royal Oak's standard?

The class would be more useful, and confidence in the second line would let Britain risk its modern battleships more freely.

Royal Oak-level modernization would make the older battleships more credible for second-line duties. Commanders could assign them with greater confidence instead of retaining modern units as insurance. That stronger reserve would let the Royal Navy risk its first-line capital ships more freely in demanding operations elsewhere. The value of the refit therefore appears in fleet flexibility as well as in the fighting qualities of each rebuilt ship.