I am concerned that I have detached from W and dropped the rope (have not communicated to her for nearly 5 weeks now, and not replied to her message or call), but W’s anger, blame and projecting are now going elsewhere, i.e my children.
You can not control her. You can just be the best DAD possible, which is what it sounds like you are doing.
She is going to have to figure out that anger, blame and projection is not going to make her a good parent. You can not FIX their relationship
Detachment comes in stages too.
You will know when you are more detached. And then there will be even further to go.
DO you want to save your wife relationship with the children? That is not something you can do.