I count him as a midfielder, because he's mostly been playing in midfield under Amorim and his role is as a midfielder. He's not on the receiving end of the balls forward, he is the one playing them. Yes he's also our top scorer because he's just our best player by a distance and is also a top attacking midfielder, even if he isn't playing as one currently.
So when I say attackers, I mean the players who are playing in attack. Zirkzee, Hojlund, Chido, Rashford, amad, Garnacho, Antony... Of which there's only Garnacho, zirkzee, Hojlund and Chido who are there now. So yes, Garnacho is our only attacker who can actually make anything happen right now. He's the only one who has good movement to receive passes in behind, he's the only one who can create a yard of space for a shot or cross when he has the ball, he's the only one the opposition has to worry about.