Jerome's work wasn’t finished till near 400 A.D. and long before what was recognized as Scripture is clear from what was quoted as authentic by writers and lists such as the Muratorian fragment.
While some books not widely circulated may have been more lately accepted amongst the Christian community, by 200 A.D. what is now called the New Testament was largely recognized as Scripture and needed no council to make it official.
Not to be overlooked is the leading of God's spirit as He has preserved His word and caused the false books like the Apocrypha to be weeded out.
“Not to be overlooked is the leading of God’s spirit as He has preserved His word and caused the false books like the Apocrypha to be weeded out.”
Then why were they kept for 1500 years?