It can be a problem if only a certain product is purchased, such as in a shopping cart on Shopify. This is a setting example that allows you to add a special tag to a product, so that if only that product is in the cart, the customer will not be able to proceed to the checkout screen. (Dynamic checkout must be disabled.)
Example of setting to prevent users from proceeding to checkout when there is only a product with the tag "Not available for individual purchase" in the theme "Dawn"
[Setup Method 1] Add a customized Liquid section to the cart screen and insert the code
[Setting method ②] Add a "Cannot be purchased separately" tag to the target product
