That's because fighting a war takes a lot of time and effort from Ukraine and Zelensky so Biden didn't fuck about, didn't waste his time and gave him what he said they need because he knows what they need. Moron Trump and idiotic Vance only see Zelensky for PR and still haven't visited Ukraine.
tbh, Biden was slow-walking the Ukrainian war effort. Pre-announcing this weapon or that, giving the Russians time to move their assets out-of-range. And then Trump's party in Congress stopped all aid at the start of 2024 for several months. Fuckers.
Ukraine got to ATACMs the helicopter bases only after they destroyed the counteroffensive.