Changing lowest scale on X-Axis continuous chart

I currently have a bunch of check-in data for various locations and ratings for the locations. Example data format is as such:

By plotting rating (Y-axis) against date (X-axis) with Averaged Rating as the value, I get a graph of how the rating of Store A changes with time: 

Due to the fact that sometimes there are no values for particular days, I want to keep the graph as continuous rather than categorical (I can use a separate graph to show the number of respondants on a particular day. 

The problem is when I add a slicer for date and show a small amount of days, the X-axis scale becomes smaller than 'day' even though the original data's smallest resolution is to day rather than hours/minutes. 

As you can see there are only 3 data values because there are only 3 days displayed but the X-axis now displays to every 6h even though the data doesn't exist at that level. The date data is stored as Data Type: Date and Format: dd MMMM (14 March) without any time format included. Without changing the graph to categorical, is there any way of ensuring that Power BI does not display measurements below a specific resolution (in this case, day)?