I also hold your OT as scripture as does Christianity. Painting with a broad brush there but yes ultimately it comes to a matter of faith and knowing you Lord and God
ZC is a Noahide, not a Pharisee-Jew. He may have been a Jesus-movement-Jew (i.e. Christian) earlier.
Anyway, the Jewish canon was edited and closed in AD 70 — and they tossed out the Septuagint and the Deuterocanonical books because those books were used by the Jesus-movement as justification for their claims.
the Deuterocanonicals in particular came under their ire as it drew and was drawing the vast bulk of 2nd temple Jews to the Jesus-movement-sect and away from the Pharisee-sect.