Hello,

Please deactivate all the plugins not related to the theme and switch the parent theme, check the issue, If the problem has gone, activate the plugins one by one, checking the issue to detect which one causes the problem.

if the problem remains, even after the plugins deactivated, please, provide your site admin access to the private area.

Please confirm the permit for us to deactivate the plugins not related to the theme and switch to the parent theme for the while of checking what may take up to 15 minutes.

As for redirecting the user to the cart page after successfully adding, you can disable this feature in the Woocommerce > Settings > Product page.

Best Regards