Hart accurately described the earliest Christology. The emanation of God spoken of at times in angelic form. SBF, you latched onto that and focus upon the word 'angel'. I see you in some ways like the host of that interview, quick to conclude Jesus was not understood as God. The larger issue of second power theology was more than a branch of angelology, however. Around 44 minutes he refers to a notion of 'secondary God' that arose consequential the transcendence of God. I'm sure if given time or encouraged to expand upon his comments, he'd have included other aspects/faces given that second God concept. The "Glory" of God" the "Prescence of God" or "Word of God". carry no angelic connotation at all yet were merged into a single concept. This fuller sense of second power fits perfectly the descriptions found in the NT. All of these faces rolled into one. Focusing upon the face of the Great Angel, especially through the lens of modernity, gives a distorted impression of how Christ/Jesus was conceived of. Hart also uses expressions like "God entering time" and "face of God" as descriptors of the Christological message of the NT which shows he is not suggesting Jesus was believed less than an emanation of God. This not the Trinity, this is not the WT.
Again, as I have been saying, the NT reveals a picture of a developing concept of deity in human form. The writers are not consistent in detail, but they are in theme. (That is why these works were selected/edited and elevated as cannon.)
He makes a number of other observations worthy of discussion, but I'll stay on topic.