What a bunch of claptrap. You’ve been smoking the Russian propaganda. The US is involved for one simple reason. Brutal autocrats need to understand that they cannot go on imperialistic campaigns with no consequence. The West is providing weapons to Ukraine to allow them to defend themselves against Russian aggression, no more no less. That is the sole motivation. To the extent that Russia has been weakened, it is self-inflicted. They could quickly stop the ongoing damage by withdrawing to the borders that existed in 2014 before Russia’s unjustified invasion of Crimea. After all Russia agreed to defend Ukrainian sovereignty in the 1994 Budapest Accord if Ukraines gave up its nuclear weapons. Ukraine did so and we can see how well that worked out for them. Do you think that Putin would have conducted either invasion if Ukraine still retained a nuclear deterrence capability? I don’t think so. Ukraine trusted Russia. They are the ones who betrayed it.
Beyond the current conflict, you also should be aware that other regimes are watching. If the West had not responded vigorously, it would have given the green light to other autocrats. Places such as China, North Korea and Iran would have taken it as a sign that they could do something similar without consequence. The West is sending a message to the autocrats and imperialists of the world that it is not permissible to terrorize one’s neighbors. The goal is simply to maintain peace, prosperity and security for the whole globe.