Remove the app blocks added on the product and cart pages in your OS2.0 version theme by clicking on the bin and hit save.

Navigate to Shopify Store Settings and select Apps and sales channels.
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Hover on the Product Options and Customizer app, and the Uninstall link will be highlighted.
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As you click uninstall, a dialogue box will be displayed titled ”Uninstall Product Options & Customizer?”
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Select a reason for uninstalling the app from the dropdown.
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After selecting your reason, you can also add your feedback.
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Finally, click on Uninstall, and the app will be removed from your store.