There isn't a strong argument that China is "steadfast in becoming imperialist." There's projection from western countries that have imperialized and colonized the global south for centuries. The liberal, western definition of imperialism you give is meant to makw any influence seem to be imperialism, it's vibes-based. A much better definition is one of extraction via export of capital, ie outsourcing and using millitary domination to force austerity on the global south (exactly the role of the IMF).

China and Russia are not imperialist by this definition, one that is materialist, and accepted by the majority of the world and not just the west.

The west provoked the war with Russia, sabotaged peace talks, and give aid in exchange for steep loans and rare earths. They are forcing Ukraine into an unwinnable war so that they can fleece Ukraine for everything.

As for Putin, generally the people and land in Eastern Ukraine are Russian, that's why the divide exists. Western Ukraine is Ukrainian. Putin's words often get morphed through a game of telephone, exaggerated, or taken out of context. He's certainly no saint, but he's also not Hitler 2 like liberals claim.