I find this rather puzzling for a customer to not have an obvious option to buy for example Digital Deluxe edition of a game that is currently owned as Standard edition. I can only buy as gift and the Digital Deluxe edition shows as Owned though only the Standard edition is available in library.

Is this actually not a relatively common demand on this store???

Thank you Ice_Mage, at first I didn't notice there are DLC files under the long list of offline files named as standard edition.

You can also check your purchase history. It will always show what edition you purchased.

Notice the word "More", upper right of a game you click. Some games have other options. Some have entirely different versions.