Unable to add a relationship between existing nodes

correct. the prior screenshot which did not include labels(n) simply indicated there were a bunch of nodes with a property 'Name' or 'name' but it did not include the detail as to what label was associated with the node. This last screenshot provides this detail.
From the last screenshot we see the 4th row has a :Album labelled node with properties Name and Released and there is but 1 node with this.
Is your goal to simply rename all property names to be lowercase? If so then

match (n:Album) set n.name=n.Name, n.released=n.Released;
match (n:Album) remove n.Name, n.Released;