Nobody in Russia who valued their business chose to incorporate it—or at least its parent company—in Russia. After Yukos, the writing was on the wall. (And now, of course, everybody who values their business takes pains to point out their chosen country of incorporation as though it wasn’t originally just a saner jurisdiction. As you’ve shown, everybody does it because it works.) JetBrains specifically did employ a fair number of both Russians and Ukrainians, though, and unlike Yandex or mobile carriers, was not prominent enough to be forced to split immediately after 2014, so it was inevitable they would have to move out of Russia (and they did so pretty gracefully).

There are no native Czech speakers in their management. It's a similar story as the Yandex guys going off to Nebius Group in the Netherlands after the invasion.

Do you know how many founders in Silicon Valley are not native English speakers? What are you even talking about?

Sure, but they're not a Russian legal entity and as far as I can see never have been (unlike Yandex). So, to the point that their being a Russian entity might be a problem for investors, it's moot, as they are not one.