Hello,
Thank you for your response.
Please check if the button can be shown with the default WooCommerce theme – Storefront activated on your site (go to Appearance > Themes > Install and activate the official WooCommerce theme Storefront for a few mins and check if your issue appears with our theme only or with the default WooCommerce theme too).
We also hope for your fast response https://prnt.sc/oZuNpyMnLzmC and cooperation. Please let us know the results of the test with a screenshot.
If the button can be displayed with the Storefront, but not with our theme, please try to disable Singl product Builder and check the button then.
Kind Regards,
8theme team