Nowhere in the UN Charter is the UNSC given the power to make international law or to issue rulings on international law. It is not a judicial body where charges are made and accused parties given rights of due process in front of an impartial group of judges.
There is an international court of justice, a completely separate body, with very limited jurisdiction. That US is not a member rightly fearing its position and its citizens would not get a fair hearing.
There are international laws that are derived from treaties under which signatory states agree to be bound and to submit disputes to designated bodies for adjudication. The UNSC is not such a body.
There is no objective international law and no institution empowered to decide what it is in the sense that the SCOTUS decides US Constitutional law.
I was raising points of law that make it clear Israel cannot be in occupation of West Bank and Samaria. There originally was a Jewish kingdom there — Jews are the indigenous people though later forcibly exiled. So all subsequent conquerers and invaders, including Arabs from Arabia, are the true occupiers. Before WWI, Jews had bought large tracts of land from Ottoman and Arabian landowners. After WWI rule was transferred from the defeated Ottoman Empire and given to Britain as a mandate to develop as a homeland for the Jewish people. This was ratified by the League of Nations. More recently, no other nation state or nationality that had claim to the lands in dispute when Israel won them in a defensive war.
If there was a fair judicial body for international law and the case could be argued before it, I believe it would rule that Judea and Samaria are in dispute, not illegally occupied. I do take your point only to extent of observing the UNSC members will usually weigh the “ real politic “ of the situation and vote against Israel, no matter if that means twisting principles of law.