Automating Brackets, and Sum above Brackets in Excel Chart

First part is easy. Just add country name to cell being used for category label.

I change the approach for brackets. Use a single data point XY-scatter series and include +/- X error bar.

So change the 2 series chart types from Line to xy-scatter.
Use select data to link cells to X and Y data ranges.
Apply data labels and show Series Name.

Select series and via Layout tab add Error Bars to each series.
Delete the Y error bars.
Select the X error bars and use the Custom button to set the plus and minus value linked to a cell.
Format error bars line as required.