Add to cart is removed from the tab order
WCAG 2.2 · 2.1.1 Keyboard (Level A)
tabindex="-1" takes the primary purchase button out of the keyboard path entirely. A keyboard-only customer can reach your product page and cannot buy from it. This is a revenue defect before it is a compliance defect.
<button class="cta" tabindex="-1">Add to cart</button>
<button class="cta" type="button">Add Winter Collection sweater to cart</button>
Why this version: Also name the button for what it adds — a screen reader user listing buttons otherwise hears "Add to cart" repeated once per product.