Hello,
You are using custom layouts for a single product page, which is why tabs are not showing on a single product page. Navigate to Layouts > edit single product page layout, and add the products tabs widget to show this: https://ibb.co/twf60QBj
You can add more global tabs (that apply to all products), you can do that by navigating to:
Theme Settings > Single Product > Tabs — under Additional Tabs, you can add more custom tabs.
If you want to be more specific and add more custom tabs for each product, you need to find a plugin.
If product tabs will not show on your site, share the wp login details so I can further check on your site and give you a possible solution.
Best Regards,