Languages not registering as "Languages supported in packages"

Question

I am having difficulty getting all but the default language of my application to show as "Languages supported in packages" in the Microsoft Store. Obviously I can add these manually as "Additional Store listing languages", which I have done, but I would rather have them show to the user as being "Supported".

My program is "damichab Home Budget", with name variations starting with "damichab" and "Home Budget" converted to the language of the store. Including the default language (English GB), I have configured 87 stores, with languages to match. With the computer set to any of the given languages, the program shows all text and images in that language.

https://apps.microsoft.com/store/detail/damichab-home-budget/9NRFBVGVGW8K

The program is a C# WinForms using the UWP bridge to create the installer packages which I upload to the store. I have recently upgraded the project to .Net7, but in any case, I could not get the stores to show in any of the lower .Net's either.

My questions relate to the documents found at:

https://learn.microsoft.com/en-us/windows/apps/design/globalizing/manage-language-and-region

https://learn.microsoft.com/en-us/windows/uwp/app-resources/localize-strings-ui-manifest

According to this section...

...the program should be reading the resource files to create the relevent stores automatically. I have done tests with both resw and resx files. No luck with either.

I tried with nameing the resource files to the language as well as the suggested folder layout as per:

But this did not work for either of the resource file types either. After the testing, I put all the resources back into a single folder with hyphens, rather than periods in the filename because something else I discovered with all this testing is that is the only way I could get the Resource files to cascade properly was to have them all together in a single folder and periods were apparently not recognised. From the program, the resources are called from Resources.Designer.cs and when a resource is missing from one file it is taken from the next most obvious file for that language until it gets to the default file, that being English.

The next thing to try was removing the <Resource Language="x-generate" /> and replacing with individual codes for each language as per...

My reading of this according to the description is that this alone, regardless of Resource files, should enable each given langauge into the "Languages supported in packages" section. But alas, and completing all tests by repeating all of the above, still no joy.

The resultant AppxMannifest.xml file seems to acknowledge the given files...

When testing with resw files, I had a single string in each of the Resouce files. With the resx files, Each one contains a number of images and a single string denoting language which is used to load the relevent class containing the strings used for that language.

At one point, I put a Control onto a form and used the designer to incorporate language options for it. That worked just fine for the program, but still did not trigger anything useful for the Microsoft Store.

With every test, I completely rebuilt the project and uploaded to the store. Nothing I did worked. I must be not doing something fundametally simple and have no idea what to do to make this work. I have included as much information and pictures that I see as being relevent. Not trying to show off my program or anything, but I figure somewhere here is a clue.

Asuming that I have to state a specific question, I humbly ask:

Given all the above and with regards to the given links, what am I doing wrong that stops this program showing everything but the default language in the "Languages supported in packages" section of the Microsoft Store?