Mostly I'd recommend listening to the podcast. https://www.ancientfaith.com/podcasts/lordofspirits/ - The "OP" accused the councils of "rewriting", but that's a harsher accusation than yours which is that the doctrine was "developing". Mostly you seem to be on my side of this issue. Also, see this from St Ignatius of Antioch: "We have also as a Physician the Lord our God, Jesus the Christ, the only-begotten Son and Word, before time began" https://www.catholicculture.org/culture/library/view.cfm?id=3836