Hello to everyone! I have modified the product-template.liquid in order to does not show the quantity selector when a product is out of stock. This is the block:
If you're still needing help with this, then I would recommend contacting Shopify Support to see if our Themes team is able to make this change on your behalf. To be eligible for their assistance, you'll need to be using a Shopify free theme and on a paid account. You can contact Shopify Support by logging into your store through the help center, searching your question/issue, then selecting "continue" at the bottom of the page that displays the search results.
If the Themes team is unable to assist you with this, then I would recommend hiring a Shopify Expert if another community member is unable to provide guidance on how to make this change.