QYLD vs ETF of the Q’s

This will sound like a dumb question, but maybe someone else is wondering the same thing:

QYLD is supposed to just be a QQQQ index that sells covered calls and distributes the proceeds every month as a dividend; correct? I’m assuming that’s not correct, because over the past year, QYLD has vastly underperformed the index.

So, why is that? Can anyone explain to me what I’m missing? Thank you in advance!