The "business reasons" by Google are probably completely fake, but we have some pointers from OP who give us the real reason :

- OP is russian

- OP was working at Yandex (who had an history of "strange" relationships with the russian government)

- in December 2022 Vladimir Poutine take over the russian subsidiaries of Yandex (through Alexeï Koudrine) -> more "strange" relationships

- OP received an official offer in December 2022

- Russia invade Ukraine in february 2023

- OP was terminated by Google in the following days in march

I am not Google, but i also would have avoided to hire a russian, just after the start of the war. I bet than all russian potential hire had been terminated the same way during the same period.

Too much red flags to take the risk to hire a potential FSB agent.