It’s hard to say; I think Beterbiev has been improving technically while regressing physically. But the version that beat Gvozdyk with today’s skill set, I have no doubt that mythical fighter would KO Bivol lol.
You make it sound like those lesser fighters survived when they didn't. It's unlikely that Bivol would do better against a younger Beterbiev. There's a reason they dragged this fight out for years. It wasn't until Beterbiev looked human against Yarde that they finally decided to fight him.
Both Bivol and Beterbiev have fought down to their competition in the past, i don't think that's indicative of how they would've looked against each other back then. I can find a couple of fights from 5-6 yrs ago where Bivol looks absolutely piss poor. The Beterbiev that fought Gvozdyk was a force to be reckoned with, just a machine. Would've been interesting to see how he would've done against Bivol today.
I agree, one thing I will say is that the beterbiev who fought bivol was probably the least muscular looking I've seen him in the ring. He used to be absolutely diced up, but this was also the same guy who was getting dropped by lesser fighters
