There are other religious themed writings among those discovered thus far that are not Jewish OT texts, or are "Deuteronanical books" either, whom no religious sect persisting to this day hold as being capital S "canonical" Scripture.
The argument promoted at the page you supplied link to, regarding the Qumran scrolls aspect (alone), is essentially; the Jews who were of the Sanhedrin, and of the Temple, did not rightly know what it was they considered as being their own Holy Writ (or that the Hebrew canon was not "officially closed" etc., until the badly dated Jamnia "conference" ---which was not like a Church Council where religious leaders got together to decide what their 'canon' of Scripture was, but instead was work to rebuild the schools of religious instruction which had existed prior to the overthrow of Jerusalem and the then further scattering of Jewish peoples hither and yon among the civilize world of the survivors of that catastrophe).
But based largely upon the discoveries in the desert near the Dead Sea, we should all now go with whatever [ahem] OT 'canon' of whichever religious persons initially hid the manuscripts, and that 'canon' be guessed at due to remains of particular writings having been found in the area. Did I mention there were other religious writings, apparently held in high esteem by those who hid them, which are not Jewish OT, and not so-called Dueterocanonical either? The fact is it is not exactly clear (as far as I know) what the person (or persons, some manuscripts could have arrived there, hidden in different place than other writings at some later date) themselves accepted as comprising their own religious tradition --of what was to be considered their own Holy Writ, and what would be lesser writings, not considered on par with "Scripture", though still important to them as religious instructions, and commentary.
Nothing you posted in any way overturned what I said. A claim was made that is directly refuted by the very existence of certain texts in the Dead Sea Scrolls. It’s just that simple.