I won’t quote both posts, but I’ll answer both...
Artur Hovanissyan is, or at least was the man. Basically, what Simon said. He won the World Kyokushin Championship once or twice, basically cleaning house when he competed. He completed the 100 man kumite, which is facing 100 men. Full knockdown rules, 2-3 minute rounds, fresh black belt every round. And I’m pretty sure he faced 2 beasts in the Kyokushin world in his final rounds - Exerton Texiera (not 100% sure though) and Francisco Filho (last opponent). He was chief instructor at Kyokushin headquarters dojo in Tokyo for a period too. He ran or runs Kyokushin in Armenia. Gotta give a shoutout to my fellow Armenian
The most recent stuff I saw from him was strength and conditioning stuff. No gi, no formalities, not even karate movements. It was in Russian without subtitles, so I don’t know what was said in it. He could’ve been aiming it at karateka or not at all. No clue. It was some pretty good stuff though.
Bassai isn’t in many Kyokushin curricula. It was a while back but Mas Oyama dropped it along with a few others. Some people are bringing back some of those kata. Kyokushin kata isn’t pretty. The main thing is the focus, determination and power. The other flashy stuff like stances aren’t the focus. I guess you could say they favor grit over flash.