I don't know where this misinformation comes from... The answer is no, reconfiguring Timer 2 does not affect millis() nor delay(), as these functions rely on Timer 0. AFAIK the Arduino core does not use Timer 2 at all. But note that there may be other Arduino or third party libraries that rely on Timer 2.

You can see here the source code of millis() and delay().

As MITU RAJ correctly states in his answer, the PWM signal on pin 11 is provided by Timer 2, so you can use it safely.

I don't know where this misinformation comes from... The answer is no, reconfiguring Timer 2 does not affect millis() nor delay(), as these functions rely on Timer 0. AFAIK the Arduino core does not use Timer 2 at all. But note that there may be other Arduino or third party libraries that rely on Timer 2.

You can see here the source code of millis() and delay().

As MITU RAJ correctly states in his answer, the PWM signal on pin 11 is provided by Timer 2, so you can use it safely.