I'm sure I don't like this Collins fellow already, and thank you for helping the ignorant masses dumb down the language with a "living language" philosophy where we race towards ambiguity.
In my world, one where people cared to preserve clarity, "couple" meant two; furthermore, "a couple of" was used "as an expression" only by those who didn't know what it meant exactly, and so they were unquotable. This is in fact why the question is asked in the first place.
Without a degree in English, this would be my logic and explanation.
"A couple" means "two."
"A few" means "three."
You might say, "I'd like a couple of them" if the pronoun has an antecedent. That is, John says, "We have a dozen peaches," and Mary responds, "I'd like a couple of them."
Similarly, one might say, "I'd like a few peaches," or "...a few of them."
Also remember, when you correct someone, you are bound to hear the living language theory. That is, the language is living and changing. Words change meanings and you can't stop that.
This gives you an out on all your errors, for who is to say that your error isn't made consistently enough to gain relevance. Also, there is no Academy of English defining right and wrong. Schools determine what is right in their institution, and a hiring manager may determine what is right. Your piers may judge helping to define right and wrong in a social circle, but as for a definitive "right" or "wrong" according to an Academy of English, there is no such thing.
I try to look at the etymology of a word and use a form that is logical and clear. The moment ambiguity creeps in, I know there is likely a better word, or meaning to be associated with the word, or punctuation to be applied to the writing.