Upromise is offering 6% cash back today at Apple through its site. This should be on top of the cash back you get using an Apple Card.
You have to sign up but it’s a reputable site. I’ve gotten hundreds of dollars cash back through them over the years. Cash back can be used to fund a 529 plan or deposited to a bank account.
I think you have to have at least $25 cash back received to move money to an account though.
shop.upromise.com