Kirill Pokrovsky passed before DOS2 unfortunately(they added an NPC for him in DOS1, and you can play his music with a spectral pianist in DOS2 <3). Borislav Slavov is an amazing composer, I absolutely LOVE his tracks for BG3 <3.
He was in Divinity 2 as well, in the Battle Tower. Seems he was a regular guest!
I remember posting a rather hastily-written and not entirely favourable review of a couple of the reworkings of his tracks for DOS. Of course in hindsight I feel terrible for doing so, I had no idea he was ill; and typically I'd simply been impatient and not given them a proper listen, so it was all rather unnecessary of me.