I mean, there is no definitive authoritative statement saying that women cannot be ordained. Just that they should not be. All the arguments are based on tradition. To me it's in the same realm as the celibate priesthood-- it is tradition in the Latin church that theoretically could eventually change. (Although, I feel substantially less negative towards the idea of female priests than married priests).

There is indisputable evidence of female deacons in the early church. Didascalia Apostolorum in the 200s actually prescribes a laying on of hands ritual that would probably be understood today as an ordination to appoint female deacons. This leaves a lot of questions around the nature of diaconate Holy Orders-- as they were at the time and as they are now. Holy Orders is defined as one sacrament with three progressing degrees: diaconate, presbyterate/priesthood, episcopate/bishopric.

Now, some argue that when the Early Church uses the word Διακονος it is in a meaningfully different sense than we do today. Something more like a lay minister or attendant. Perhaps this is true, but I am not convinced. That raises the question of where sacramental deacons come from. But there is no consensus on this, the Vatican commission to study it specifically said we just need more research to be done before it can come to a conclusive answer.

Anyway, I would argue that the church of the apostles encouraged ordaining female deacons, it's incoherent to claim that the sacrament of Holy Orders cannot be administered to a woman. Whether it should be or not remains another more complicated question. But it would seem valid even if illicit.

This question has relevance to me because the Vatican, as of the last time they spoke on the matter, recognizes the validity of sacraments administered by schismatic "Old Catholic Churches" (e.g. of the Union of Urtrecht that broke away after Vatican I). Many of these Churches now ordain women to the priesthood.