I always remember Justin Ledet. Was 3 and 0 as a 265er in UFC, undefeated. He was 6'4'' and 240 pounds but didn't look shredded or anything. And he was towering over these 6'1'' fat fucks that fight there. Gave a boxing lesson to all of them because they are all slow, fat and have no cardio.
Then he moves down to 205. First fight was against Alexander Rakic. 6'5'' and shreded. He looked much bigger than Ledet and wrestlefucked him easily, no 265er had been able to take him down, none of those fat fucks even tried I think. Then he goes against Johnny Walker, 6'6'' also shredded. Get knocked out in seconds. Then Dustyn Jacoby, smaller but actually a skilled striker with Glory experience and knocks him out in 1 round again. Poor bastard retired in disgrace. He didn't move down, he "moved up"... in competition when he left the overweight division
Yes, Walker would do great. That division is horrible. The problem has always been the top of the division. In one you have Blachovich and Jamahal Hill, on the other one you have Cyrill Gane and Francis Ngannou. Big difference if you want to be a champion.