There is a difference between prophetic language describing the “house of Israel” and practical language describing an individual.
The language used when referring to how something is a thorn in the side of a people (Israel), is the same sort of language used when God describes Israel as “playing the harlot” when seeking after false gods. This used to illustrate a point.
In the case of a person (such as Paul), there is no need for figurative language, since Paul IS a person. Paul on many occasions referenced the Judiazers and named names - why would he “code” a reference when he spoke if this issue directly in other places?
Remember the ORIGINAL issue/question is “Can God’s people suffer physical illness? Can bad things happen to God’s people? Will they be poor, or all massively rich?”
Is this then (the idea of claiming Paul did not have physical issues) back up that view?
Let me ask then, Why then did Paul have another write his letters in some cases, and then sign them, saying “see what big handwriting I use”, evidently due to his poor eyesight as he aged.
Want to argue that? If so, then why are the Health/Wealth preachers on TV wearing glasses in many cases? Why are they not healed of poor eyesight?
Health/Wealth/Word of Faith is ANOTHER Gospel — it’s not THE GOSPEL.
Those that sit on gold colored thrones and preach on TV and claim their followers are having their fillings in their teeth replaced with gold are false teachers. That is NOT the gospel.
No time right now, so just a quick reply to one thing. "Thorn in the flesh" IS figurative language. Obviously Paul did not have a real thorn sticking into his flesh. The question is what does the figure of speech mean. Scripture answers Scripture, and Paul was a Hebrew with Hebrew understanding, and the understanding of that figure of speech was that it meant people causing vexing, and problems, not a physical ailment.
Your other points can be addressed apart from the point about what "thorn in the flesh" clearly meant/means, as they are in other contexts.