You "cannot" edit that list. Anything other than what's in there, would be 'custom'. You can create Favorites for each of your sizes from the window manufacturers that you use.
(Editing the list requires knowledge of GDL coding... and would be in the Developer Hub > GDL forum.)
PS. I can tell from your screenshot and dimensions that you are using the USA library/localization. It is important when posting questions to list your version of AC, the localization and your OS... see my signature as an example.
One of the forum moderators AC 27 USA and earlier • macOS Ventura 13.6.2, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB