I teach half a dozen classes relating to the UN and international law. Your interpretation is plain wrong. You don't get to pick and choose which part of the UN Charter to follow based on their order in the document. Sovereignty is the default principle, while the right to self-determination is extremely constrained. To obtain self-determination without consent from the country you're seceding from, you need to start with the decolonization committee in the UN General Assembly. Then you need their report to be voted on by the entire UN GA and sent to the Security Council. Only the Security Council can require self-determination, and it would have to be justified in terms of its contribution to international peace and security (though the SC makes that determination for itself). Since decolonization, no one even considers this option unless crimes against humanity are taking place.
As someone who doesn't take international law seriously, it's odd that you'd point to aspirational parts of the doctrine. To be meaningful, it must be codified in binding treaties and conventions. There must be some mechanism for punishing violators. While that is the case for sovereignty, by far the dominant doctrine in international law, there's little to none for self-determination for non-colonial countries. Even genocide-prevention has a weak role in international law relative to sovereignty.
So don't take us for idiots by pretending that your interpretation of the UN Charter is somehow on par with that of the actual UN, diplomats, and international jurists.