Great post because i noticed this aswell.
Zirkzee isnt lazy, ive kept an eye on his pressing and he actually tries really hard - however Zirkzee is actually quite slow so it looks like he cant be arsed to press when actually he cant high press because he is slow. He is like a trying hard version of Berbatov who both lacked pace.
Usually for this you will see that Zirkzee tries to make the high press as much as he can but sometimes drops quite deep because he can be more useful defensively that way.
Hojlund is the better high presser but ive been surprised that even his pace has gone down a level it seems compared to last season
Garnacho-Zirkzee-Amad
Is probably my preferred line up with Garnacho and amad almost playing like the Rashfords of each side as we saw when Zirkzee and Rashford combined quite well vs Everton.