Ukraine has repeatedly asserted that the HQs of all their major units are intact and as far as I know there have been no announcements of any Ukrainian generals killed and as far as I see even Russian media have not contested that. With some searching on the Russian internet, I find some assertions in Russian social media from early March that Lt Gen Юрій Содоль commanding the Ukraine Marines was killed, but not anything conclusive. So the number seems to be 0, or perhaps 1. And IMHO
that isn't surprising, it's quite normal to fight major wars without many generals KIA, it is very surprising that Russia lost so many of them.
Even on colonel level the losses seem to be small - I think that this https://www.republicworld.com/world-news/russia-ukraine-cris... this was the first Ukrainian ground force colonel KIA that I recall, there was at least one air force colonel before that.