I like the 4-4-2 idea as an option, and I think Gyökeres makes more sense in that context. I am warming to him as a box player, I like his movement and his actions. Quick and forceful. I think there are concerns about his open-space power and pace translating to the Prem – he can be fine but not dominant/elite. You don't want to give him too much technical/tactical responsibility. But you have Havertz(Merino) as the roaming out ball and Gyökeres(Trossard) as the predator, I can see that working. That said, I'd feel better about it if he had a track record with headers. We cross the ball a lot, and he is straight up weak finishing with his head. Hopefully he's Attacker #2 and we sign a bigger player out wide.
Sesko would be more of a powerhouse on the counter, but with Havertz we don't need another striker whose best quality is physicality. He seems kind of redundant. And Mikel has to get over needing max physical advantage in every player in the team.