Quranic createdness

I see, however the Ash'aris don't believe the Qur'an (i.e. the Arabic Qur'an composed of letters) to be eternal, they say it's created. In fact I've been told by several Hanbalis, Ibadis and even Ash'aris themselves that the dispute between Ash'aris and those who believe its created is a verbal dispute. Would you agree with this?

For example, in Aqeeda Nasafiya just before your quotation he mentions "He Speaks with an Eternal and Everlasting Speech which is not of the kind of letters and sounds and it is an attribute that negates silence and defect.". In the 'Sharḥ Aqeeda Nasafiya' by the Ash'ari scholar Taftazani, he mentions under "The Qur'an—the Speech of Allah the Exalted—is not created":

"He (Al-Nasafi) mentions the Qur'aan Kareem after mentioning "the Kalaam of Allaah", due to that which the Mashaayikh have mentioned that, the Qur'aan is the Kalaam of Allaah Ta`aalaa, uncreated, and it is not to be said: "The Qur'aan is uncreated," in order to avoid the understandings of people jumping to the conclusion (if it is said as such) that that which is made up of sounds and letters is eternal, which is the position that was adopted by the Hanaabilah out of ignorance (jahl) or obstinacy. [...] The Mu`tazilah inferred that the Qur'aan is attributed with that which is from the attributes of the creation, and by marks which show its origination (hudooth), such as composition and arrangement, and being sent down and being revealed bit by bit, and its being in Arabic, and being heard (by the ears), and being eloquent, and being inimitable, etc. That only acts as evidence against the Hanaabilah, not against us, because we believe that in the arrangement being originated." ( here , 98-111)

And Bayjuri mentions in his hashiyya p160:

"And the madhhab of Ahl us-Sunnah is that the Qur'an, with the meaning of al-Kalaam an-Nafsi is not created. And as for the Qur'aan with the meaning of the lafdh that we recite, then it is created. However, it is prohibited that it be said, "The Qur'aan is created" intending by that the lafdh - except in the context of teaching. Because it may give the presumption that the Qur'aan, with the meaning of His The Most High's Kalaam (i.e. His attribute of speech) is created. And for this reason, the scholars withheld from speaking with the Qur'aan [being] created"

Juwayni says in his Irshad after mentioning those who believe the Arabic Qur'an to be eternal:

"Moreover, their principle that eternal speech becomes incarnate in bodies although it does not separate from its essence makes idle sport out of religion, loosening the tenets of the Muslims, and imitating the doctrine expressed by the Christian in their holding that the word inheres in the Messiah, who is equipped with human form. If it were not that many people are deceived into embracing these notions, the situation would not warrant paying attention to these obvious disgraces and outrageous abominations"

There's quite a few more confirmations from Ash'ari/Maturidi scholars regarding this