Hey just so you know, a change to this law was approved just a couple of days ago. I don't think it has passed yet but it is fully expected to. I'm not totally familiar with all of the consequences, and there may be an exception for you, but this excerpt seems relevant to you:

"The decree-law approved today states that Italian descendants born abroad will automatically be citizens for only two generations: only those with at least one parent or grandparent born in Italy will be citizens from birth."

I'm really sorry

Reddit link with more info

La procedura per il riconoscimento si sviluppa nei passaggi di seguito indicati:

accertare che la discendenza abbia inizio da un avo italiano (non ci sono limiti di generazioni); accertare che l’avo cittadino italiano abbia mantenuto la cittadinanza sino alla nascita del discendente. La mancata naturalizzazione o la data di un’eventuale naturalizzazione dell’avo deve essere comprovata mediante attestazione rilasciata dalla competente Autorità straniera; comprovare la discendenza dall’avo italiano mediante gli atti di stato civile di nascita e di matrimonio; atti che devono essere in regola con la legalizzazione, se richiesta, e muniti di traduzione ufficiale.

The main point here is that you could get citizenship from your great-grandfather only if he was still Italian when you were born IIUC.

Would that be still the case for you? Would any of the family members in between be Italian by any chance?

Read this, then run to an Italian consulate and see if/how you can start the procedure. Do it on the double because the law is about to change.

In order to get that you need to have submitted the request for citizenship before 27 march 2025. They changed the law after that, before any kind of relative born in the 1800s was enough (a bit ridiculous imho), now only up to parent or grandparent.