Line chart, display one day per week without changing the graph format.

When you use "Categorical" mode, every value in the x axis is displayed.  When you use "Continuous" mode, Power BI selects which X Axis values to display if there isn't room to display them all.  At this time there is no way for the user to create a sort of customized X axis where every value in the chart is displayed but some custom list of X axis values are displayed, for example, "Display every x axis value where the weekday is thursday".

I even went down a rabbit hole of experimenting with conditional formatting of the X axis value, but apparently there is no filter context in the axis so even if you make an additional calculated column with the weekday and specify that "if weekday = 4, color should be black, otherwise make it white", that doesn't work either.

If you solve this I'd love to be wrong because there are a few reports I'd modify.

///Mediocre power bi advice, but it's free///