The next version of an international council needs actual authoritative power. There’s no point if someone just decides they don’t want to listen and will do whatever they want. Veto power should be curtailed if a supermajority of countries are in agreement otherwise a bad actor will push their weight around.
The same argument holds up to any government doesn’t it? Why have a government that can enforce legislation since it could one day be infiltrated by actors I don’t like? Isn’t the point of most democratic governments that they handle local issues at one level of government, national issues at another but at all layers have some method of enforcement and including the voices / will of the voters? I’m not saying they’re perfect, just that your argument against a UN with more teeth seems to apply to all governments