I wonder what you make or scholars like James Dunn in that case. As far as I can make out he was a Trinitarian Christian and remained a Trinitarian Christian to the end of his life. Nevertheless his honest historical study of the NT led him to conclude that the conception of God as a Trinity was a later development, that only God was worshipped in the highest sense in the NT, and that Jesus was separate and subordinate to God. That’s not just a quote here or there, that’s a fair reflection of what he wrote as whole.
Catholic scholars, such as Raymond Brown and Joseph Fitzmyer, can be very illuminating too because, unlike Protestants, Catholics can tolerate the fact that the Bible doesn’t necessarily present a fully Trinitarian view because they rely on tradition in addition to the scriptures. Raymond Brown and Joseph Fitzmyer seem to have had a degree of freedom to admit where the Bible says things that are inconvenient. For example Raymond Brown’s discussion about where Jesus is and is not called God is quite illuminating because he narrows it down to fewer passages and with narrower meaning than many Trinitarians would like.
Paula Fredriksen is Jewish but her scholarship (it should hardly need to be said) ought to be judged on its merits. Any fair appraisal of the competing reconstructions of early Christology by Fredriksen and Hurtado, for example, would conclude that she makes better sense out of the available evidence.