In other words, it is not at all surprising that we find virtually every Jewish authority before the second century acknowledge the belief in 'two powers' in heaven. Not only in the Book of Daniel:
One verse reads: “His throne is sparks of fire (Dan. 7:9) and another [part of the] verse reads, “until thrones were set up and the Ancient of Days sat (7:9). This is no difficulty: One was for him and one was for David. As we learn in the ancient tradition: One for him and one for David, these are the words of Rabbi Akiva. Rabbi Yose the Galilean said to him: Akiva! Until when will you make the Shekhina profane?! Rather, One was for judging and one was for mercy. Did he accept it from him, or did he not? Come and hear! One for judging and one for mercy; these are the words of Rabbi Akiva. [BT Hagiga 14a]but more importantly for our purposes - the revelation at Sinai with one power speaking from the fire and another from heaven.
It was only by the second half of the second century that any sort of framework for interpreting the Pentateuch (which features two distinct divine names) 'monotheistically.' Indeed if we imagine that the revelation at Sinai - the 'culmination' of the Exodus experience explicitly demonstrates two powers (so the marginalized Jewish traditions at the end of the second century) it stands to reason that there were two powers - i.e. one of judging and one of mercy - during the entire Exodus narrative. This understanding survives in Marcionism because, one must imagine, it developed before the influence of monarchianism and undoubtedly suffered because of its rejection of this mandated 'innovation.'