Numbers 24:9 is the verse that states that those who support and help Israel will be blessed and those that curse it cursed.
There’s no biblical mandate to support modern Israel.
To me, Romans 9:8 and Romans 11:13–32 (especially verses 30–32) summarize this well. In Romans 11:26-27, Paul is referencing the promise in Isaiah 59:20:
“The Redeemer will come to Zion, to those in Jacob who repent of their sins,” declares the Lord.
But that promise is conditional, it’s directed at those who repent. And you can't repent of the sin of denying the Holy Spirit, the very testimony of Christ, if you refuse to even acknowledge that He exists!