It seems to me that things really were a jumble in the early Church. Yes, the Septuagint figured prominently in early church usage (though not always in the way people think). Yet we also find statements like this by St. Athanasius:
"There are, then, of the Old Testament, twenty-two books in number; for, as I have heard, it is handed down that this is the number of the letters among the Hebrews..."
Sts. Jerome, Hilary of Poitiers, Cyril of Jerusalem, Gregory the Theologian, Epiphanius, and John of Damascus (and also Origen) make a similar argument (based on the Hebrew alphabet) as to how many books they accept in their canon. Also, while many early Fathers quote from the deuterocanonicals, sometimes even calling them Scripture or saying that they are divinely inspired passages, the majority (especially in the East) didn't accept them as part of the canon. Fwiw, here's a rough draft overview of the passages in the early Fathers in which they seem to attribute divine or scriptural status to deuterocanonical texts...
The usage and canonicity of the deuterocanonicals among the early Fathers following the Biblical period is hazy. St. Clement of Rome mentioned Judish (Epistle to the Corinthians, 55), but past that we have nothing certain: at most a couple possible quotes or allusions, with Epistle to the Corinthians perhaps meaning to use Wis. 2:24(3), Wis. 12:12 (27), and Sir. 4:29 (34). These links are tenuous at best. Other possible quotations or allusions can be found in St. Ignatius (Epistle to the Magnesians, 3; cf Susanna 52), St. Polycarp (Epistles to the Philippians, 10; cf Tob. 4:10 and/or 12:9), and Tatian (Address to the Greeks, 7; cf Wis. 2:23). In Pseudo-Barnabas we do fine a quote from Sir. 4:31 (Epistle of Barnabas, 19), and another from Wis. 2:12 (Epistles of Barnabas, 6), which is probably a mistake (as it seems to be attributed to Isaiah), though it does show that Wisdom of Solomon was read enough that it had sunk into the conscious of the author. The only early quote that seems indisputable is found in the usage of Sir. 4:31 in Didache, 4.
Toward the end of the 2nd and into the 3rd centuries we still have a bit of a mixed bag, with St. Melito of Sardis rejecting almost all the deuterocanonical books (according to Eusebius in Ecclestiastical History, 4, 26), but with St. Irenaeus using the books a bit more than earlier authors, quoting or alluding to the additions in Daniel, Baruch, and Wisdom of Solomon multiple times. Tertullian quotes Baruch (Antidote for the Scorpion’s Sting), the story of Bel and the Drgon (On Fasting, 7), mentions Judith (On Monogamy, 17), and perhaps mentions Tob. 12:12, though he could be referring to other Scriptures (On Prayer, 16). Tertullian also quotes Wisdom of Solomon multiple times, and attributes the work to Solomon (Against the Valentinians, 2; Against Marcion, 3, 22; Prescription Against the Heretics, 7). St. Hippolytus did a commentary on Daniel, going into Susannah, characters from the book of Tobit, and also mentioning 1 Maccabees. And finally, Pope Callixtus quotes Tob. 4:15 as “sacred Scripture” (Epistles, 2, 5).
It is when we get to St. Clement of Alexandria, however, that usage of the deuterocanonical books starts to seriously increase. St. Clement is especially familiar with Sirach and Wisdom of Solomon, though he also quotes the story of Bel and the Dragon (Stromata, 1, 21) and Judith (Stromata, 2, 7; cf Stromata 4, 19), and calls both Tobit (Stromata, 2, 23; 6, 12) and Baruch (The Instructor, 2, 3) Scripture. As for Sirach, St. Clement quotes it four dozen times in just the Stromata and The Instructor, calling it Scripture many times (The Instructor, 1, 8; 2, 5; 2, 8; 2, 8; 3, 3; 3, 4; 3, 4; 3, 11 and 3, 11). St. Clement also quotes Wisdom of Solomon nearly two dozen times in the Stromata and The Instructor, calling it Scripture once (Stromata 5, 14), instead preferring to introduce the passages as from Solomon or “the divine Wisdom”. (Stromata 4, 16; 6, 11; 6, 14; 6, 14; 6, 15; 6, 15; 6, 15). Origen also used the deuterocanonical more frequently, quoting from them dozens of times in his Against Celcus, On First Principles, Commentaries on the Gospels of John and Matthew, and other works.
St. Cyprian of Carthage also quoted frequently from the deuterocanonical books. Tobit is quoted quite frequently, being referred to as “Holy Scripture” (Treatise 4, 32) and from the Lord (Epistle 51, 22), and St. Cyprian also accepts the words attributed to the Archangel Raphael as authentic (Treatise 4, 33; 7, 10; 8, 5). St. Cyprian also considers the books of the Macabees to be “Holy Scripture” (Epistle 54, 3) and quotes them multiple times, in addition to also quoting Bel and the Dragon, Susanna, and the Song of the Three Children (Epistle 55, 5; Treatise 12, 3, 20). In one place he introduces the story of Bel and the Dragon with the word: “Daniel, devoted to God, and filled with the Holy Spirit, exclaims and says…” (Treatise 11, 11); likewise concerning Baruch, he introduces a quotation of Bar. 6:6 with the words: “The Holy Spirit, moreover, suggests these same things by Jeremiah, and teaches, saying” (Treatise 4, 5).
St. Cyprian seemed to think that Solomon wrote Sirach (Seventh Council of Carthage of 258; Epistle 54, 21; Treatise 12, 3, 53; 12, 3, 95; 12, 3, 113, etc.) Nonetheless, despite the confusion, St. Cyprian still considers it a book inspired by the Holy Spirit (Epistle 64, 2) and “Sacred Scripture” (Treatise 8, 2). Regarding Wisdom of Solomon, like St. Clement, St. Cyprian prefers to introduce his dozens of quotations from this book as being by Solomon, saying things like: “the Holy Spirit teaches by Solomon” (Treatise 7, 23) and “The Holy Spirit shows and predicts by Solomon, saying…” (Treatise 11, 12). He does also say, however, that Wisdom of Solomon is “sacred Scripture” (Epistle 80,2).
The deuterocanonicals were not neglected by other ecclesiastical writers, being quoted for example by St. Dionysius of Alexandria several times in the extant fragments (Books on Nature, 5; Epistle to Bishop Dionysius of Rome, 4; Epistle 10: Against Bishop Germanus, 4), and introducing one passage from Sirach with the words: “listen to the divine oracles” (Books on Nature, 3). Other 3rd century authors to quote or allude to the books in question include Achelaus (The Acts of the Disputation With the Heresiarch Manes, 29), St. Victorinus (On the Creation of the World), and others.
Closing out the 3rd century and bringing us up to the time of the First Ecumenical Council, we have a number of other writers quoting from the deuterocanonical, including St. Peter of Alexandria (Fragments, 5), St. Alexander of Alexandria (Epistles on the Arian Heresy, 1, 5), Lancantius (The Divine Institutes, 4, 8; 4, 13; 4, 16), and many passages in the works of St. Methodius, including a quotation of Wisdom of Solomon that is called Scripture (Concerning Chastity, Theophila, 3), and introducing another passage from the same book with the words: “And in the Book of Wisdom, a book full of all virtue, the Holy Spirit, now openly drawing his hearers to continence and chastity, since on this wise…” (Concerning Chastity, Marcella, 3)
Again, this is only a rough draft, and also only based on the texts available in the Schaff Ante-Nicene Fathers collection. But clearly, whatever the canonical status, many early Fathers highly valued the deuterocanonicals, and so one would think that we too should read them and search them for wisdom and insights.