This is a really fascinating subject for me, and (by my lights) currently ranks as one of the most plausible contexts for generating ur-Qur'anic texts. A great article on the connections between 5th-6th century anti-Chalcedonianism, Arabia, and Christological controversy.
https://www.academia.edu/731430/A_chapter_in_the_pre-history_of_the_christological_controversies_in_arabic_Readings_from_the_works_of_John_RufusIt seems to me that much of the earliest Qur'anic texts could be explained as originally derived from an ascetic missionary context, which is precisely how the Arabs were first Christianized by Peter the Iberian -- a miracle-working anti-Chalcedonian monk who was bitterly opposed to the Jerusalem Byzantine orthodoxy. Over time, the Arab recitations and short texts which resulted from this process would have continued with that thrust away from the Byzantine heretics (as anti-Chalcedonian monks would depict them), and developed innovative theology that diverged from the Syriac Qeryana that was recited as liturgy; they could also have developed such innovations over the course of the 6th Century as they diffused Southwards, away from the Transjordan.