Not really we have that already in Hojlund, the issue is more how the side combines to create chances as you could argue that when playing both Rashford and Garnacho we have two forwards who want to get narrow and behind teams to score, so it suits us to have a striker like Zirkzee who wants to drop deep and link play so that you have a set of complementary runs being made (one player starting high and dropping deep, whilst others start deep and try to get in behind).
The problem with Hojlund is it's part of his natural game to want to make the same type of runs as Garnacho and Rashford (the type you describe in behind) so it makes us less cohesive and predictable. Its no coincidence that we look a more fluid side when employing a false 9 for this reason.
Zirkzee movement and hold up play should open up scoring opportunities for the whole team, its then up to us to be more clinical but the fact that we create so little for Hojlund and would likely do for another striker like him is down to the two forwards either side of him who are much more goal driven than creative. Zirkzee should balance that out.
I don’t think that’s true at all, I think Garnacho is very much a creator as well as a goal threat.