Kownacky not fast enough to trouble top heavies but fair enough he have strong jaw and he is good at combination punching and countering his opponents.
Kuzmin is a fringe contender level heavyweight, not too bad but not a real contender. I think Kownacki would beat him. Chisora-Kuzmin would be an even matchup. Kuzmin would beat former Wilder WBC title challengers like Gerald Washington, Chris Arreola and Artur Szpilka.
I can say this, if you can't get in shape fight after fight, you need to reevaluate your life choices.
I hope he gets himself in shape. He is not awfull by any means but he has seriously damaged his chances of winning belt or reaching status of contender. I'm so tired of out of shape heavyweights. I can understand that you are out of shape for one or few fights but all the time, let's get serious folks. It's bad for health and skills, nevermind the chances of suceeding. So far he is behind likes of Husein Muhammed, Demerizen, Romanov, Bepo Filipi, Dubois and some other up and coming heavyweights, nevermind the top heavies.