I need a column that is between the backlog and the sprint.

Call it "Ready for Development" or "Defined" or whatever.

The Backlog is where new requirements land.

The "Defined/Ready for Development" column is where they move after they have been force ranked and estimated.

Sprint planning involves pulling from the "Defined/Ready for Development".

Having this ability is a huge benefit to managing the project and should be considered a mandatory feature.