Thank you so much for contacting our support center.
To better assist you, could you kindly test the functionality with default WordPress themes such as TwentyTwenty or WooCommerce Storefront? This will help us determine whether the issue stems from our theme or elsewhere.
Could you please disable all plugins that are not related to our theme and switch to the default theme so we can check the add to cart speed and then switch to WoodMart and compare the results?