No need to create 1:1 mapping between routing configuration and queue.
Routing configuration helps in deciding logic of allocation like Most Avaiable/Least Active and capacity consumption to be considered when one work item from queue is assigned to the agent.
Queue is something which holds work items till the point they are not assigned to someone.
In your case you can go ahead and create as many queues as you want and associate with only one routing configuration. All items will be treated based on the configuration done in routing configuration independent of what items you have added in queue like lead, case, etc.
Consider below snaps:
Queue List Veiw
Routing configuraiton - Shwoing multiple queues
As per above you can attach multiple queues to the same routing configuration. In order to do that you need to edit queue and select routing configuration that you want to use.
So when to consider associating queues with different routing configurations:
Queue helps you classifying work items lets say case could consume 5 unit of work but lead could consume 10 units of work then in such cases you need different routing configuration.
Hope this answers your questions.