Is there ambiguity in this sentence, or does prescriptivism preclude it?

Hi!

I have a grammar question. Which is probably a lot of the posts on here (though, TBH, I've actually never been here before, I'm just so bothered by this particular situation that I thought, that's it, I'm going to Reddit and asking).

So, I'm going to rewrite the original sentence...hopefully I've done it properly. I'd appreciate some help either explaining myself or understanding precisely why I'm dumb:

"The woman's friend is about to nominate her in a contest because she described how he treated her in an awesome manner."

The original was very much about a different topic, but I believe the structure is the same.

In this sentence, I said that I felt there was ambiguity--that it could be read as "The woman's friend is about to nominate her in a contest because she described how he treated her in an awesome manner" or "The woman's friend is about to nominate her in a contest because she described how he treated her in an awesome manner." In the former, she's being nominated because she described how he treated her, but did it in an awesome manner, and in the latter, she's being nominated because she described that he treated her in an awesome manner.

I said context clues made it mostly clear that the latter was meant, but that the former was also a valid reading. I said that in general, the former was the reading that would be expected (if it was a "plain" object, like "The woman's friend is about to nominate her in a contest because she described the cat in an awesome manner.") and, given the broader context in which the line appeared, in particular given that the reading has less explanatory power in the latter reading (if she didn't do it awesome, why is she being nominated?), I was genuinely uncertain even though I was pretty sure.

The response I got was that that was an invalid reading, that according to prescriptivist grammar it was not just clear but aggressively unambiguous.

I was told that in English grammar, a modifying phrase or clause (such as the prepositional phrase "in an awesome manner") is understood to modify the nearest modifiable phrase or clause; that though I suggested that "in an awesome manner" could adverbially modify she described (as in, "she described in an awesome manner") rather than how he treated her (as in, "how he treated her in an awesome manner"), I only did so because I failed to appreciate that the modifier is actually attached to the clause it modifies and is (for that same reason) remote from the other one.

I feel like that's not necessarily true, but I also feel like I'm too rusty at my fancy grammar wordstuff to be certain and that I don't have the words ready to explain myself.

Part of me thinks that if it was really truly unambiguous "that" would be substituted for "how"?

Fundamentally it's really bothering me that I'm not really understanding my own position well enough in terms of being able to describe it and/or understanding that it's wrong.

So at the risk of being long-winded, am I being crazy and foolish, or is that sentence ambiguous?

Thanks!

**Edited a typo because of course there was a typo.