In fairness to Byrd he was skilled and pretty slick; I don't think Usyk would destroy him. Most likely it resembles the Hunter fight somewhat, with Byrd giving a decent account of himself early doors, before Usyk takes over and puts a beating on him, possibly (or most likely) getting the stoppage. Saying all that has me reminiscing about Usyk-Hunter round twelve; no idea how that wasn't stopped, surely a modern record as to the most unanswered punches a fighter has absorbed without the ref stepping in.
Byrd was very durable to be fair he took huge punches from a big puncher like Wladimir and went 12 rounds. Ibeabuchi was a monster 230+ pounds and the shot Ibeabuchi floored Byrd with would've knocked out a horse and Byrd still got up. I think Byrd would go the distance with Usyk it would be a good technical fight with Usyk coming on strong in the later rounds with his higher workrate and aggression winning in the region of 8-4 ? Maybe the judges would have a bit closer ? As for the unanswered punches record Spinks landed 84 punches on Cooney in the 5th round of their fight I think that has to be up for the record for unanswered punches.
At some point, Hunter turned his back, it I remember correctly. Should have been an immediate stoppage.