Jesus was a Jew. His God was the Jewish god. Jesus was circumcised ie Jesus was within the Jewish God's covenant (explicitly in Luke 2:21, implicitly in Mark, and thus the synoptics. The author of John however is keen to distinguish Christians from Jews, so that case is a tad less certain).
The moment Paul abandoned God's covenant with the Jews by abolishing the requirement of circumcision, Paul was no longer worshiping the God of the Tanakh. Instead he had created the God of the NT, who kept some resemblance to the God of the Tanakh, and (in Paul and in John but not in the synoptics) acquired some resemblance to the God of the Gnostics too.
And if there's one thing none of the five NT versions of Jesus are, it's being God or any part of the triune God. The Jesus of Mark and the Jesus of Matthew did NOT say, "Me, me, why have I forsaken me?" and none of the gospel Jesuses said "If it be my will, let this cup pass from me." Instead, all five versions state that they're NOT God and never claim to be God ─ I set out their express disclaimers in an earlier post here >
Jesus Failed Right?<.
So Jesus didn't become God, and the Christian God didn't become triune, until, after two or three centuries of church politicking to elevate Jesus to God status, the triune God was accepted in the 4th century.
The triune God is NOT the god of the NT, and even less is [he] the God of the Tanakh.
On top of it all (or, underneath it all, if you prefer), the triune concept is incoherent. I set out some of the problems here >
Creation vs. Evolution<.