Hello,
To disable automatic option selection in the Prestig theme go to your Shopify admin panel navigate to “Online Store” > “Themes” and click “Actions” > “Edit code” on the prestige theme. Find the relevant file like theme.js or product-template.liquid and look for any code that selects an option on page load like $(‘#product-select’).val($(‘#product-select option:first’).val());. comment out or remove this code. Save the changes and test your store to ensure the automatic selection is disabled.