Probably for this reason.
- In February 1917 the Soviets took control of Russia.
- Ukraine, which was part of the Russian empire, immediately claimed autonomy from the Soviet take over.
- in October 1917 the Bolsheviks took over Russia and invaded Ukraine.
- November 1917 the Balfour Declaration was created, establishing the nation of Israel.
When the Kazarians (the Rothschilds, etc) saw they would lose their center of operation, they decided to create their own sovereign country.
They can be both "on their side" and "in opposition" at the same time. There are levels of compliance. There are also layers upon layers of deception. I suggest that thinking as straightforward as you suggest is not appreciating those layers.
You said they "lost Ukraine." They never lost Ukraine. They didn't lose it when the USSR invaded Ukraine, and they didn't lose it when the USSR collapsed. They orchestrated both the initial "takeover" and the collapse of the USSR.