Supporting developers is great. Let's pretend that these are 100% zero-bad-intent developers. If they're still a Russian company (and they are, with offices in Moscow and St. Petersburg), then they are taxed, heavily, by the Russian government. That isn't a maybe. That is simple truth. A meaningful portion of any money spent on this game will, absolutely, no question, end up in the coffers of the Russian government.
Buying the game would mean that my money may well go to buying a bullet fired at Ukrainian soldiers, or to execute a Ukrainian civilian.
And even one such bullet resulting from my decision is too many. Even the possibility isn't OK with me. It isn't like there's nothing else I can be playing, not given the cost of playing this one.
And that's all assuming that they are, as I said, zero-bad-intent. The evidence suggests that they aren't. And yeah, they're headquartered in Cyprus, not Russia. The tiny island of Cyprus isn't where people go to escape Russia. It is the place Russian companies legally move their headquarters to bypass anti-Russian sanctions.