I feel you, Idapro. I also don't like having to scroll the bottom bar just to see the full picture of a report. When the report appears to be stretched or split, the best fix is to ensure your page zoom is set to 100%, which is the default setting. Once you've adjusted the zoom, click the Refresh icon within the report section. These steps will surely bring the column widths back to normal and get everything fitting on one page again.
As for merging the columns into one, it’s not something we’re able to do because maintaining the separation of data allows for easier adjustments to column widths.
You can refer to this screenshot below:

Let me know how it works for you.