When did the change occur in meaning of Afghan from an ethnic group to "person from Afghanistan?"

A related question can be found here, dealing with the usage of "Afghan" to mean "inhabitant of Afghanistan." Which term is correct — "Afghan" or "Afghani"?

I'm interested in figuring out when the usage of Afghan as "an inhabitant or Afghanistan" overtook the usage of Afghan to refer to what we now call the Pashtun people. Is it possible to pinpoint how and when this change occurred?

Etymonline says:

Afghan: name of the people of Afghanistan, 1784, properly only the Durani Afghans

Wikipedia describes the Durrani Dynasty as being founded by:

...Ahmad Shah Durrani at Kandahar, Afghanistan. He united the different Pashtun tribes and created the Durrani Empire

So, the term Afghan enters English properly referring to the ethnic Pashtuns.

MW.com says:

First Known Use of Afghan 1742, in the meaning defined at sense 1a(1)

1a(1) : Pashtun

borrowed from Persian afghān "Pashtun"

A Britannica entry on the Lodī dynasty says:

The dynasty was of Afghan origin.

The word Afghan in the entry includes a hyperlink to the entry for Pashtun.

So, it is clear that the term has been both historically used and is currently being used as another term for the Pashtun people, who are only one ethnic group that makes up the inhabitants of the nation of Afghanistan. Though at some point the term also came to be used as a generic.

The reason this question occurs to me is that there are quite a few people claiming that Afghan is the correct way to refer to someone from Afghanistan. It seems that logically the way to refer to someone from Afghanistan would actually be Afghanistani, in the same way we refer to people from Pakistan as Pakistanis. Compare the difference between Tajik (ethnic group) and Tajikistani (nationality), Turkmen (ethnic group) and Turkmenistani (nationality), Kurd (ethnic group) and Kurdistani (inhabitant of the region),etc. Though, Afghanistani seems to have so little traction it was not even mentioned in the related question I linked above, and appears to have no hits in Ngram.

Does anyone know how and when Afghan became accepted as the way to refer to inhabitants of Afghanistan, even when they were not ethnically Afghan?

Both meanings seem to have been in simultaneous use for a period of time. This 1845 book uses the term in both senses, inconsistently: the Uzbeks and Baluchi are part of “our Afghan conquests” on page 51, but on the very next page, an army is composed “partly of such of his Afghan adherents as still followed his fortunes, and partly furnished by the Uzbek rulers ....” Another book from 1847 uses “Afghan, or Pashto” in its title, explicitly as synonyms. So, by the mid-1840s, “Afghan” is like “German” or “Italian”: it can refer to a geographic region, the language predominantly spoken there, to one ethnicity, or to anyone living in the area.

By 1899, however, this book is unambiguously referring to “the Afghan peoples” as a multi-ethnic term for residents of Afghanistan. So, the shift appears to have taken place in the mid-1800s.

An “afghan” as a word for a type of shawl is attested from 1833, and more things became called “afghans” up until the present, such as an afghan (sweater) from 1975 on.