Bulk deletion of node which are unpublished and which are in between the given dates
I suggest to use the Rules module for that.
Bulk deletion is explained in one of the first tutorial video's in this series:
https://drupalize.me/videos/introduction-rules?p=1157

What you should do:


enable Rules and Rules UI
create a new Component of type "action set"
actions to add: a loop thru the nodes and if the date matches, the node should be deleted


The Views Rules module might be usefull to use views to send the nid's of the nodes to delete to the rules component.
I learned a lot about this via the accepted answer to "How to pass arguments to a view from Rules?".

An alternative could be the Views bulk operations (VBO) module, which has a "bulk deletion" out of the box. You add a VBO-field in your view and select the "delete" as the action. Maybe this is even better than the Rules (in the way that it will take less time to understand and implement).