You will need to create a global page for this so that it has access to all projects.
If you want to use a widget to do the visual graph then you’ll need to set the type to Canvas (found at the bottom of the list).
If you want to add this graph as a tab to an existing global page then just choose the Canvas option in the View type field of the new tab.
Go into design mode of your new page/tab, add a graph widget and choose the Shot entity.
I highly suggest setting a Filter rule first to avoid trying to graph too much data and freezing sg when your doing this on a global page. For example, set a filter to remove and shots that have your “Tag” field as empty since I’m guessing shots that don’t have the tag filled out are not needed here.
You will want to then set the Graph option to your Tag field and Group by Project. Then you may want to use the Stack Type as “Regular” if you want to simplify the view but thats up to you.