I am using the latest version of PowerBI Desktop "Version: 2.124.1805.0 64-bit (December 2023)" but am having trouble creating a table matrix in the way that I want to. I have managed it once before with a different dataset but I unfortunately do not remember the steps and I have tried a number of things. All my datasets are exactly the same with the same headers. I remember doing this just by using the Rows/Columns/Values options in the "Build Visual" screen. Any help would be appreciated.
The first image you provided is Power Query Editor view, here you only set the date type, no data formatting.
Come out of the Power Query Editor and into the main PBI Desktop. Now here, select the table column, and in the ribbon, under Column tools, you can define the formatting...
Or are you looking for Switch values to row groups rather than columns
option, under Visual Properties > Visual > Values > Options
For your Matrix have: