If we try to explain it away: wanting to torment him by leaving him to die last; villain monologue syndrome; them having concussions from Kuma/Luffy
It looks stupid either way. Making Vegapunk's death your "top priority" and then never actually going through with a concrete attack on him is pathetic.
Ironically, the person with the most Vegapunk kills this arc is Vegapunk (York killing Shaka)