they rejected Jesus because God had blinded their minds to not see that He was the Messiah.
Jesus HAD to die and if they had recognized Him for who He was, they would not have had Him crucified.
1 Corinthians 2:7-8 But we impart a secret and hidden wisdom of God, which God decreed before the ages for our glory. None of the rulers of this age understood this, for if they had, they would not have crucified the Lord of glory.
It wasn't a matter of amount of knowledge, but of understanding it.
The information was there. They didn't get it.
So, based on your post here, reread what I originally
>>As I said in my previous post, the God that we know and understand today is not the one of the Jews of Jesus’ time, the God of the OT.<<
What again is wrong in that statement?
The Jews did not understand God in the same way that Christians do regardless of why that was then or remains so now.