I was expecting Google has stopped doing most of the business in Russia due to sanctions. Do you still see Russian-company ads in Google Search results or Youtube? Similarly, I thought they were not selling apps or ads in Google Play store in Russia either (they might be showing ads from non-Russian companies because, well, that just increases the show-count and absolute number of clicks).
I no longer reside in Russia, so I am not being targeted by these.
But I think that it mostly comes down to companies being able to pay for these ads. Mastercard / Visa payments no longer work in Russia. If a company has a way to pay (by having another business entity in another country), then it probably works.