I understand why the founding UN nations have veto power but surely someone brought up the idea of hey someday one of those nations might become a problem we have to address how should we do that if they can just block our resolutions? Surely some dudes thought of a contingency.
It's kind of an impossible problem to address. The main thing the UN exists to prevent is a WW1-style entrenchment of opposing camps. It's not very good at it, but that's what it is attempting to do. Notable that the United Nations is the real name of what we now call the "Allies" of WW2. It's the winning team of a world war, imposing world domination and world government. If the Axis had won (and they were so inclined as to impose this sort of system, which they probably wouldn't), then you'd have a Germany/Italy/Japan permanent security council triumvirate, with the UN called The Axis instead.
Here are some mid-WW2 propaganda posters for the United Nations, which we now call The Allies:
After setting themselves up as a 5-member council to rule the world forever, fortunes have changed. Some of the Great Powers of Yesteryear have become irrelevant (Britain, France). China has become immensely more powerful than it once was, in terms relative to the other permanent security council members.
Being legally locked into a de jure framework that is no longer representative of the real world balance of power is one of the big reasons wars happen. It is one thing for a rebellious kid to envy the power of a big strong man, but it is another matter when the kid grows up to be a rebellious big strong man, envious of an old man who is frail and weak. Somewhat related to the concept of a
Thucydides Trap. What is the UN supposed to do? War is the main mechanism by which these de jure/de facto dissonances are righted. Frail old men are not wont to give up what they see as theirs, and it must often be taken from them by force. In many cases, one could see war as a 'necessary evil,' juxtaposed with propping up a moribund and dysfunctional status quo.
Russia having the power to veto a resolution against their war of aggression, because they have a permanent security council seat, may seem absurd and dysfunctional, but that is the nature of an organization whose goal is to promote peace or prevent war; preventing war as conflict resolution prevention. The only way to stop Russia's war of aggression in Ukraine is with another war waged against Russia. Either Russia gets to tell America to fuck off with their veto, or America has to tell Russia to fuck off with ICBMs to Moscow.
As much as it may suck to watch the sympathetic Ukrainians getting fucked over, there is very little that can be done about it through the international community. Ukraine is as natural and vital a part of Russia's sphere of influence as Canada is to the US. The Euromaidan coup conducted by the US glowies was a very provocative move by the USA. You could make comparisons to the Cuban Missile Crisis, or the Chinese conducting a hypothetical coup d'état in Canada; the US would not tolerate it. Ukraine becoming a NATO/EU/etc member and entering the Western sphere is such a fundamental threat to Russia that they have a willingness to put it all on the line to prevent it. That being the case, what is the UN supposed to do about that? The only way I can imagine a way for the US to keep Ukraine in the Western sphere of influence would essentially be to destroy Russia; most likely to balkanize them, or give them the Austria-Hungary treatment, along with maybe a nuclear equivalent to Sherman's March for good measure (along with denuclearization of the various post-Russian rump states). The USSR already balkanized, which is one of the causes of this conflict, so further balkanization would need to be designed carefully so there could be no further resurgence in future. This would only even be possible if the veto were removed from the UN security council, and would still probably not be desirable to almost anyone involved.
The UN is a stupid, ineffectual body with questionable aims. Life is struggle, and struggle is life. There is only one way you can have peace, and that is to surrender. You can have peace only by submission and surrender, living as a slave. Peace, on the other hand, is death. Rest in peace. The ancients recognized this. The very name of Jerusalem is sometimes translated as the House of Peace, but in fact it is the House of Death. "Jeru-" means "house of," and Shalim is the Canaanite sunset god, in a pair of twin gods of dawn and dusk; sunset, death, peace. If you want to live, you must struggle and fight. The onetime Great Powers of Western Europe may have rolled over and submitted to America, but look were that got them. It is no wonder Russia instead opts to fight.