The Alexandrian Jews did. That's where the Septuagint came from and was used by them canon. Obviously, the Apostles thought they books were canon because none objected to those books being there, just as no one objected to quoting from the Book of Enoch.
Different Jewish communities had different canons. Even within the same sect (Rabbinic Judiasm) heterodoxy is the norm in that religion. "Jewish" canon was not settled until much later, and then I wouldn't call it "Jewish" since other sects (Alexandrian Jews, Essenes, Sadducees and Samaritans) are also Jews, and the Masoretic text of the Tanakh doe snot represent their canon.
The Protestant canon follows the Pharisaical (rabbinic) canon, a sect unto itself that survived and is erroneously conflating it with 1st century Judaism in general.
“Obviously, the Apostles thought they books were canon because none objected to those books being there, just as no one objected to quoting from the Book of Enoch.”
No. They often cited the OT, saying, “It is written...” (”Then Jesus said to him, “Be gone, Satan! For it is written, “’You shall worship the Lord your God and him only shall you serve.’”)
The quote from Enoch is similar to the quote of the Cretan prophet. (”One of the Cretans, a prophet of their own, said, “Cretans are always liars, evil beasts, lazy gluttons.” 13This testimony is true.” vs “4It was also about these that Enoch, the seventh from Adam, prophesied...”)
You speak as if there was one Septuagint. Though some Hellenized Jews may have read one or more versions of the Septuagint they were hardly the "Jews".
"The Protestant canon follows the Pharisaical (rabbinic) canon, a sect unto itself that survived..."
Do I understand you to be claiming that the present day Jewish Canon (Torah) of the Orthodox and Reformed Jews is nothing but a surviving sect?
Romans 3:
[1] Then what advantage has the Jew? Or what is the value of circumcision?
[2] Much in every way. To begin with, the Jews are entrusted with the oracles of God.