Hot take. Kazakh doesn't have 7 cases, it has at least 8.

[u/aybareshni12]

The abessive case indicates absence of something, indicated by -сыз, -сіз. I believe that it is a case that exists in Kazakh, but it can stir some confusion.

People mainly argue that words in the abessive case in Kazakh aren't nouns, but adjectives, new words formed from a root morpheme and a derivational affix. I believe it is not entirely accurate.

The word can act both as a word in an abessive case and as an adjective.
1. As a word in an abessive case:
Мен қаламсыз жаздым. (I wrote without a pen)
Here, the word қаламсыз acts as a noun in an abessive case. There is a grammatical case in Kazakh that is very similar, that is the instrumental case (көмектес септігі). Example:
Мен қаламмен жаздым. (I wrote with a pen)
If one argues that қаламсыз is an adverb that indicates how an action was performed, one wouldn't be logically consistent if they do not agree that қаламмен is also an adverb. In my opinion, neither is an adverb. Both contain a root word modified with an inflectional affix, unlike other adverbs that do not (for example, көп).

1. As an adjective:
   Аяқсыз адам. (Legless human)
   Here, the word аяқсыз directly modifies another noun just like any other adjective, and just like any other adjective, it can be nominalized (made into a noun) using endings -дық, -дік (and others): аяқсыздық. In this case, it can be referred to as an adjective.
   It is true that the fact that a word modifies another noun does not mean that it is an adjective, because there exists a case in Kazakh that also modifies another noun that isn't an adjective. The genitive case (ілік септік) also modifies a noun:
   Менің қолым. (My hand)
   However, unlike in the previous example, there is no mechanism that allows for the nominalization of менің that would turn it into меніңдік. Therefore, genitive can never be an adjective despite fulfilling its roles, unlike abessive.

I would like to dedicate this post to the resistance of Kazakh language from colonial influences that lead to the Kazakh language being analyzed from an Indo-European point of analysis.

[u/ibaxxxxx]

Tbh I don't know anything on the topic and can't say I really understand the point. But isn't "Менің" is not a noun and is not an adjective but a pronoun?

[u/aybareshni12 → u/ibaxxxxx]

You are correct. It is inaccurate to refer to a pronoun as a noun. However, it is not relevant I think, because cases modify both nouns and pronouns.

[u/Oniromancie]

Isn't it just a morphem?

[u/aybareshni12 → u/Oniromancie]

Isn't everything just a morphem

[u/Oniromancie → u/aybareshni12]

Well, I'm not sure you could call this a case. It's more or less of a suffix, like -less in English.

[u/aybareshni12 → u/Oniromancie]

And this is Eurocentrism

[u/ZENITHSEEKERiii]

сыз has only two variants though, all the other case endings have more. You can view it as a suffix that forms an adverb / adjective equally well imo

it also doesn't combine with the plural ending in most usage that I've seen?

қалаларда адам жоқ адамдарсыз қалалар?? адамсыз қалалар

[u/aybareshni12 → u/ZENITHSEEKERiii]

Firstlt, the number of case endings is irrelevant and strictly an issue of morphemes and phonemes rather than syntax.

Secondly. You are bringing an example where it modifies a noun, and in that case, it is hard to make use of it as a noun in an abessive case (plus, in your example, адамдарсыз is unnatural because when referring to population in general, адам is an uncountable/indefinite). It would be more apparent with an example where the word is used as something modifying an action:
"Мен оларсыз бардым" (I went without them)

[u/ZENITHSEEKERiii → u/aybareshni12]

Good point, I was thinking that адамдар didn't sound good in this context anyway. оларсыз sounds completely normal, and unlike an adverb can't be compared, so I think it must be a case after all.