I'm a fellow user, not a TurboTax employee. Did you happen to choose the "up to 5 days early" offer? This is secondhand info, but I've seem some users say they had to remove and decline the "up to 5-day early" offer to get to the screen about the Refund Advance. And one user said scrolling down is a small link for "other options" to get to the page with the offer. So hopefully that will make the Refund Advance offer appear for you.
Here's more info. Read it carefully:
FAQ: What is Refund Advance?
https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-refund/refund-advance/L52Mg0G5u_US_e...