magento2 – Product grid – sorting by custom field – not treating as integer

I have a Magento 2.4.1 site where I’ve added a custom attribute to store a discount percentage. I want to sort a category by this value.

However, in the grid list view (based off the Luma theme), it treats the percentage saving as a string. For example, it orders them as follows:

…instead of:

The attribute is configured as:

  • Catalog Input Type for Store Owner: Text field
  • Input Validation for Store Owner: Integer number

Is there a way to force it to be treated as an integer so it orders properly?