I’m not a Catholic (yet), but might I suggest that the numbers are a polemic to the even more ridiculous numbers of the Sumerian king list and creation stories? A lot of Genesis is a polemic. Like an inside joke of the ancient world, if you will… one where outsiders in Sumer or later Babylon would recognize (or even Egypt in creation story of God’s Word making the sun rather than God being the Sun/Ra himself), and would purposely anger them. Stories where they share similar origins (Noah and Enoch are in multiple sources, for example), but the Bible always turns it on it’s head. Maybe there was even a symbolic significance to the numbers they chose (almost all of the ages are divisible by 5, for example).
I would say Abraham’s whole life specifically was a polemic. He was from Sumer (even his dad, “Terah” means priest in Sumerian… and they came from Ur, which was the temple of the moon god). Old apocryphal stories even have a young Abraham smashing his dad’s idols (which his dad apparently made) and causing a ruckus to the public. The bible doesn’t get into this, but it’s a very believable backdrop why God called him out of the land and made a new, breakaway civilization (which would eventually bless the world through Jesus Christ).