Yeah he's faded and vulnerable but at his peak he was a level above them. All 3 of the others have shown weaknesses and vulnerabilities. Bivol and Gvozdyk are not special. Bivolis smooth and fast but not really vicious, kind of like Joseph Parker. Gvozdyk is stiff and awkward he didn't look the way an elite prime fighter should look against at a 40(!) year old when he fought Stevenson who was on his last legs. Beterbiev has truly special power but.his competition has been mediocre recently after a very good start of his career against cloud and campillo. He has been badly mismanaged by Icon Michel imo and the Canadian trainers are no good and can't teach anybody anything new. Lemieux Alvarez Beterbiev Pascal none of them look that well schooled to me. All of them seem to basically just be in good shape and have retained their amateur skillsets but all of them would have done better with a different trainer imo. Kovalev at his peak was really above these guys and he is declining but surely not to the point where he can't give the top 3 a hard fight.
I expect him to be competitive and having a shot against any of them, but favor him against none. My H2H list at 175 is like this. 1. Bivol 2. Beterbiev 3. Gvozdyk 4. Kovalev I expect Bivol to outpoint Kova or stop him late. Beterbiev to steamroll him inside the first half, maybe going down once himself. And Gvozdyk to win by scrappy late stoppage.
Hopefully these guys mix it up and there's more than zero or one fight between them in some combination. I feel Kovalev has a good shot against Beterbiev.