Hi,
The simple answer is that it would work as you expect. If you use “Delete a list of things” and the query returns only one item, it will remove only that one item. If it returns many, it will remove those. If it returns none, it will not remove anything.
You’d use “Delete thing” (the one for one item) when you can specify in your query the item that you need removed. Note that your query in this case could also return an empty set and in that case, nothing would be removed. Also, you can indicate that you want to remove a thing (Bubble’s parlance for a record) manipulated in a previous step (Result of Step x) or one of the parameters passed to the workflow.