The only thing I would disagree with is your opening assertion: “The book of Hosea is not about matrimony in any way.”
We can observe directly from the skip-letter codes in the Torah, that the Bible contains many levels of meaning, revelation and prophesy. Even in the plain text we have noted multiple fulfillment of prophecies. It is like a hologram that is encoded with many wavelengths and orientations of light.
Remember: He is the potter. We are the clay. Don’t try to tell the potter what He is about.
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“A people for My Name” is the subject that Yehova presented in Hosea.
Marry a harlot was simply an instruction to the prophet.
When Yeshua discussed the paying of tribute with Peter, did his instruction to Peter to take a coin from the mouth of a fish make it about fishing? :o)
(I agree that the ancient scriptures have many layers of information for those that seek it)