Based on your comment:
So when I retrieve everything from this org and convert it the .csv appears in my force-app>main>default>staticresources directory in my DX project. I'm trying to access it from there and use it in a test class
You are trying to use a local CSV in your test class to load data -- you cannot do it this way.
The way you load data from CSV files in your test classes is from the Static Resource within your Org. So whenever your test class executes, and that you have the CSV file being referred in your test class, it will always look for the file there instead of anything locally. Remember, everything runs on the cloud/lightning platform and thus there's no dependency on any local content.
Refer to the below excerpt from Loading Test Data documentation:
You must create the static resource prior to calling this method. The static resource is a comma-delimited file ending with a .csv extension. The file contains field names and values for the test records. The first line of the file must contain the field names and subsequent lines are the field values. To learn more about static resources, see “Defining Static Resources” in the Salesforce online help.