"Watchtower wants followers to think that the Bible Canon was closed by the Apostles, not at some later period by the Church."
Not quite so, is it?
I agree with what you say, but my comment is not that Watchtower says it was closed by the Apostles, but wants people to think it was closed by the Apostles.
To illustrate, Watchtower says Jesus is mediator for only the 144,000, but most JW's do not know this because Watchtower rarely refers to this teaching, because their doctrine is quite offensive. They are happy for JWs to misunderstand their teaching, which is why when they rarely discuss the mediator doctrine and when doing so frame it so it is very difficult to understand their teaching.
In a similar way, Watchtower knows the Apostles did not choose the canon, so do not state that, but they like to leave that impression. IMO, the quote from OP is misquoted with little benefit to do so than to leave the impression the Apostles and/or first century Christians were responsible for deciding on the Bible Canon, rather than the "Church" at a later period. They regularly speak about the apostasy occurring after the death of the Apostles, and how John wrote the final books of the Bible, so that JW's will assume the Bible Canon was completed by John. I certainly thought that way until I left Watchtower and did research outside Watchtower publications, despite spending a lot of time going through All Scriptures Inspired.
When Insight, Volume 1 p. 409 discusses the Canon, it states "Outside the Scriptures themselves there is evidence that, as early as 90-100 C.E., at least ten of Paul’s letters were collected together. It is certain that at an early date Christians were gathering together the inspired Christian writings." It then goes on to discuss how the Early Fathers were quoting the NT books. Again, this does not say the Canon was closed by 100, but as I read these quotes as a JW, wanting to believe God directed the Canon, I thought that is what it meant.