So Wanda practically kills Thanos here without the stones. In Infinity War, she keeps him at bay for a while when he has all the stones.
Yet she has problems protecting herself and the Vision from Thano's henchmen, Doesn't it sem inconsistent?
In Infinity War she is trying to protect herself and Vision from Thanos while trying to kill Vision at the same time since she is trying to destroy the stone so Thanos can't get it. But in Endgame she can fully focus on Thanos and sends all her powers towards him instead of multitasking.
shareI think its down to her being scared to use her powers to their fullest after the events in Civil War when she tried to stop Crossbones blowing everyone up, but ending up killing some innocent bystanders instead.
In Infinity War, shes more interested in protecting Vision, and also most of the fighting between her and Proxima Midnight wasn't to Scarlet Witchs advantage.
Now that shes had to watch Vision die twice and now has a chance to exact some justice, shes going all out now to try and kill Thanos.
So i don't think its because of inconsistency, its down to reluctance at first.