Try to edit the slides with the page builder and check the responsive settings. You must modify these elements within the responsive settings of slides in page builder, which you are using Elementor or WP Bakery, according to the specifications of the mobile device: https://elementor.com/help/mobile-editing/
Additionally, navigate to Slides > Edit Slide > At the bottom of the slide, check the slide settings for mobile devices: https://ibb.co/Vc5rG8dL
If you have any questions, feel free to contact us.
Navigate to Theme Settings -> Single product -> Enable the option Custom tabs. Then you will be able to add the custom tabs via Dashboard -> Products -> Custom Tabs.