Commenting on the “Esdras” issue and its relationship to the April 1546 decree of the Council of Trent on the canon, Catholic apologist Gary Michuta admitted that, while practically impossible, it is theoretically possible to view the Catholic canon as being “open”:
On March 29, 1546, fourteen questions (called capita dubitationum) were proposed to the council fathers to provide direction for the framers of the document. Question four asked whether the books that were not included in the official list of the canon, but were included in the Latin Vulgate (the book of Esdras, 3 Ezra, and 3 Maccabees), should be rejected by the decree by name or passed over in silence (Concilium Tredentinum: Diariorum, Actorum, Epistularum, Tractatuum [Nova Collectio] edidit Societas Goerresiana, Tomus Quintus. Question four of the Capita Dubitationum, 41, lines 30-31). Only three fathers voted for an explicit rejection. Forty-two voted that these books should be passed over in silence (Latin, libri apocryphi sub silentio). Eight were undecided (Ibid., 52, lines 22-32).
Therefore, not only did Trent not explicitly reject the book of Esdras, but the fathers did express a wish that the decree not name these books as being rejected. This is a subtle but important point; It’s not altogether accurate not say that Trent “rejected” the book of Esdras.
Does this mean that Catholics can accept the book of Esdras as canonical Scripture or that the contents of the canon of Scripture is an open question? Not at all. The canon of Scripture is that is given at the Council of Trent, the Council of Florence, and the African councils. I suppose it could be theoretically possible at some future date to admit Esdras to the canon since it was never explicitly rejected, but this would be practically impossible since the book has fallen into disuse. (Gary Michuta, Why Catholic Bibles are Bigger [2d ed.; El Cajon, Calif.: Catholic Answers Press, 2017], 322-23)
On the issue of the canonicity of the Apocrypha, be sure to check out:
A good, scholarly but accessible, volume on the Apocrypha by a Latter-day Saint that I recommend is that of
Jared W. Ludlow, Exploring the Apocrypha from a Latter-day Saint Perspective (Springville, Utah: CFI, 2018)