Can I use the gift card to get credit on a MacBook Pro I just purchased?

No, you can not transfer funds from an Apple gift card to your Visa.

You should have it re-done at the Apple store by returning the Mac, re-purchasing the same Mac but this time using the gift card.

That is not possible.

Are you talking about using your gift card as a payment for your Apple Card? If so, no.

Thank you for commenting but I do not need your assistance.