It still doesn't really matter what the UN says because the ICC can't prosecute non-members. The US is also not a member of the ICC nor did we sign onto the Rome Statute even though we helped write most of it. The most the UN can do is impose sanctions against Israel.
ICC can indict & prosecute anyone. They just can’t extradite people. To wit, bibi and others have already been indicted in absentia for war crimes. Notably absent from the writ is genocide, because apparently the grand jury didn’t have enough UN “leading scholars” on it. 😂
The ICC can only prosecute non-member individuals under specific circumstances. Not states. And the specific circumstances are if the individual commits a crime in a member state, if the accused is a national of a member state, or if the member state allows the ICC to prosecute an individual.