Explain to me how Putin is not a Hitler-esque strongman again?

I mean, he hasn't done any major genocide yet or have the cult of personality,

You just answered it. Putin is a generic authoritarian leader like Russia has had for centuries. That power vacuum is worrying, and I think he's definitely comparable to Bismarck. The mass populist movement, retreat from the global market, genocidal nativism, none of these are there.

Putin seems driven by his experiences in the KGB during the end of the Cold War, feeling the leaders at the time betrayed the country to its enemies, and is seeking to reclaim the past glory of the Soviet Union.

But he does so in the context of the current bureaucratic framework in Russia, which is still bought-in to the global marketplace. Hence also making "Lisbon to Vladivostok common market" statements. He capitalizes on national conflicts, whether in Georgia or Ukraine, when it's in the interest of boosting his poll numbers and scoring points against the West. These are to be expected from any rival strongman.

Going out and overturning every tinpot leader who opposes us is an easy way to stir resentment and breed actual Hitlers taking that power vacuum in reaction, especially in Russia's case with their already extant siege mentality. Look at Iraq for an example on a much smaller scale than Russia. Instead, you contain said strongmen. The transition from one tinpot autocrat, to a weaker one, to a weaker still one is exactly what's called for and essentially describes the Western transition to liberal democracy.