Deportation and fines of course. They are like 6.000.000 pesos.
And what could happen to the OP(s), the parents of a child was born in Argentina and is a citzen if they go to migraciones and apply for temporary residency?
What, if any, could be the negative consequences of "both (being) foreigners who have overstayed by a significant amount of time (and)...spent (the) majority of the time between early 2022 and today in Buenos Aires, (and have) only spent 5-6 months of that time elsewhere, on 2 & 3 trips for both of us, respectively. I have 3. They weren't "visa runs." (They) left for months at a time on 2 occasions."
I am assuming that while they have been living here that he/they have been engaged in some form of economic activity which generates the income on which they are living and, as I indicated in my first reply in this thread, if I was in the same situation, I would not go near the office of migraciones...at least (I am adding here) not before I was absoutely certain that migraciones would grant the temporary residency solely based on being the parents of a child born in Argentina, without any negative consequences of failure to comply with any of the laws that apply to any of my previous actions in Argentina. If I was in a similar situation, I would also want to know if the mother of "our" child, might be able to claim that she wasn't working and be granted temporary residency while I, even as the father of the child, could be fined and deported after my temporary residency is denied.
Based on Bajo_cero2's answer about the consequences of going to migraciones while working en negro (even with permanent residency), and, even if I only wanted to stay in Argentina for two or three years at this point, I would apply for citizenship under the previous law, unless I was sure that being the parent of a child born in Argentina provides immunity from the immigration regulations that otherwise would apply to me.
And I wonder, even if Argentine migraciones cannot deport an Argentine born citizen of any age (especially a baby), they can order the deportation of the parents, assuming they would take their baby with them if deported. and/or levy millions of pesos in fines for working en negro, an activity that has never been acceptabe with temporary residency, which going forward, appears to require proof of financial support by legal means more than ever.
If neither of the parents are or have been working en negro in Argentina (including online with foreign clients), perhaps the temporary residency would simply be granted. Nonetheless, I imagine that migraciones will want proof of the (passive source) of the foreign funds they have been and will continue living on. If I understand correctly, this is not likely to be a major issue with a citizenship judge.
Continuing as I indicated in my first reply in this thread, regarding what I would do if I was in the same situation as the OP, I would seek advice from an Argentine attorney who has experience with these issues, not from someone who never had an overstay or made a border run, never worked en negro, or fail to declare taxable Argentine income, and actually paid a lawyer to help them get temporary residency in Argentina, only the last of which does not apply in my case.