How do you introduce a non-quote?

Initially, I drafted the following sentence.

He argues we consistently make assumptions that are wrong.

Later, because it looked like a quote, I added a comma. But, do I need a comma?

He argues, we consistently make assumptions that are wrong.

However, the sentence is not a quote. I am simply summarizing a seminar I attended, and I have found I am using this sentence structure often. Plus, for the sake of variety, I would like to flip this basic structure.

We consistently make assumptions that are wrong, he argues.

Unfortunately, I have searched both my "Chicago Manual of Style" and "The Chicago Guide to Grammar, Usage, and Punctuation" with no luck at finding any examples highlighting this condition.

For a moment, I thought CMoS Section 6.27 applied. In my example sentence, maybe that is implied. So, I thought I might have found my black-and-white answer. I don’t need a comma. However, it seems odd to me that we consistently make assumptions that are wrong would be considered a restrictive relative clause. If I were to drop he aruges, the sentence is still complete. Plus, relative clauses are normally shorter. Lastly, Section 6.27 did not provide any direction if I were to flip the sentence.

Subsequently, I also found CMoS Section 6.42 which comes close as well. However, it deals with questions, not statements. But, its example sentences are quite close to my example.

Thus, I dove into the sections on sentence structure in "The Chicago Guide to Grammar, Usage, and Punctuation," researching subject, object, and verb. However, as I watch the clock, I have realized I need expert help. I understand there are often no black-and-white answers, but can anyone point me to the correct section related to the structure of my example? Can someone help me understand the parts of my example sentence as they relate to any particular "rule" in CMoS? Is that implied? Is the comma required? Is the comma only preferred? May I flip the sentence? How does it relate to the rules of a quote? Are these two independent clauses? I think there are many technical ways to approach my question, and any one answer would help me dig out of my rabbit hole.