(Parts) of Ukraine only came under Russian rule in 1686. The Cossack Hetmanate fell under Russia rule and Habsburg rule later, similar to how Poland fell under Russia and Prussia.
While I don't believe Putin is a Communist and consider your claim that he supports a more classical great Russian nationalism very plaussible, he did restore the Soviet anthem in 2001.
Worse, he has outlawed historially accurate statements regarding Molotov-Ribbentrop. Defended Soviet horrors against Poland.
I also find it telling that with a supermajority in both houses, Putin didn't pass a constitutional amendment protecting unborn life. The gay marriage ban was lowhanging fruit, but it doesn't seem like Putin is willing to crack down on more popular sins. Nor does the patriarch seem to pressure him in any way.
The Catholic Church in Poland has done far more even while Soros money was sent to create mass protests.
Benedict XVI was cracking down on those homosexual scandals and what caused him to retreat exactly, I don't know.
At least his loyal prelates like Vigano, Muller, Burke, Eijk, Sarah, Zen, Pell and so on are bravely continuing the fight.
Pell and Zen are true examples of martyrs.
But Kirill has not shown any interest in antagonising the pederasts within orthodoxy. He seems to be fine with it being swept under the rug.
Fr. Kuraev got defrocked for speaking up about how at least 14 % of the orthodox bishops had covered up abuse.