I enjoyed this article from Crisis. I'm familiar with the author. I've seen him on EWTN a few times speaking about the Lord of the Rings. Apparently, this is a fairly common interpretation of the poem but it was NEVER presented to me that way not even in Catholic school.
---
Snip
Structurally, the poem is divided sequentially by Beowulf’s fighting with three monsters: Grendel, Grendel’s Mother, and the Dragon. The battle against the first two monsters is a parable of the necessity of God’s grace and the consequent rebuttal of the heresy of Pelagianism, which was rife in England at the time, as is evident from Bede’s Ecclesiastical History of the English People written at around the same time as Beowulf. Like Bede, the Beowulf poet is warning against the dangers of this heresy, which taught that men could go to heaven by the power of their own will, by merely doing what the Bible teaches, and that, therefore, they did not need the supernatural assistance which theologians call grace.
https://www.crisismagazine.com/2021/...-in-a-nutshell