Is there a way of having a widget on a ticket dashboard that shows how many tickets are in the queue & have yet to be assigned to an owner?

I think there is not an easy way to do that. I am thinking in using a mix of status and ticket flow. you create a new status called not assigned and a flow that say that the ticket goes to that status 1 hour after is created. and then goes to in progress 1 hour after the last actualization. in that case you can find the not assigned tickets