Instant checkout via shortcode?

Is there a way to implement an instant checkout button via shortcode, or only with the Gutenberg button widget?

Is the "Direct Checkout" link for a variation the same thing as the "Buy Now" button that would trigger the instant checkout? If so, would creating a button WITH that link open instant checkout?

Also, it appears that the Gutenberg “Buy Now” button option adds the modal that duplicates my cookie widget in the lower left corner.