Would Graf Zeppelin and Aquila overstretch the Royal Navy?

Would completed German and Italian carriers, Graf Zeppelin and Aquila, stretch Royal Navy carrier strength badly?

Yes, but both carriers would also become priority targets for repeated British night attacks.

Completing Graf Zeppelin and Aquila would create a real carrier-allocation problem for the Royal Navy, especially if both operated in or affected the Mediterranean. Each ship would nevertheless attract repeated British night attacks. The carriers would therefore need to survive concentrated efforts to disable them before their air groups could reshape the theater. The answer acknowledges the additional strain without treating completion of the two ships as automatically decisive.