Hello, @jimmy,
The issue you are facing is because you have used/created your site and products using the Elementor page builder, and now you are trying to edit the product description using the default Text editor and that is the reason it is not reflecting on your site, you have to edit the product description using the Elementor page builder and it will work for you, Please watch this video: https://www.veed.io/view/6a9053dc-6a62-4dfe-a487-6e56c1ced238?sharingWidget=true
Regards 8Themes Team.