They never had an Empire as the Soviet Union.

But they did. That's why Mao called them social imperialists.

As for NATO, it's to ensure western imperialism stays intact. The US is the main beneficiary, but western Europe participates because they also profit from brutal exploitation of the global south.

That just brings into question how NATO is a threat to Russia then? The only way that would be true is that either a) Russia sees them as imperialist competition, or b) the threat is that Russia can't attack its neighbors without retribution.