system.IO.Directorynotfoundexception for the file that exists in the network drive

I am trying to open and fill a blank .pdf file. This blank .pdf file resides on the network drive. The path to that blank .pdf file is specified in the program.cs file. When I tried to read the blank .pdf file in my code, my code automatically goes to C:\ drive to read that blank .pdf file rather than the network drive. This is what I have in my code:

I have the following code in my program.cs file:

app.UseStaticFiles();
var configValue = builder.Configuration["ConfDestinationPath"];
var blankPDF = builder.Configuration["BlankPDFConfig"];
app.UseStaticFiles(new StaticFileOptions
{
    FileProvider = new PhysicalFileProvider(configValue),
    RequestPath = "/testForm" // URL path
});
app.UseStaticFiles(new StaticFileOptions
{
    FileProvider = new PhysicalFileProvider(blankPDF),
    RequestPath = "/BlankPDFForm" ,
    // URL path
});

this is what I have in my my appsettings.json file:

"ConfDestinationPath": "\\\\tcs-trs\\shared\\2024\\LanguageForms\\",
"BlankPDFConfig": "\\\\tcs-trs\\shared\\2024\\LanguageForms\\BlankPDFForm\\"

I have the following code in the controller:

string filledPDF = "/testForm/";
string blankPDF = "/BlankPDFForm/"; 
blankPDF = blankPDF + "TestForm.pdf";

Here, when I am trying to read pdf file, TestForm.pdf that resides in the network path, I get an error saying system.IO.Directorynotfoundexception and it looks for the TestForm.pdf file on C:\ drive rather than on this network drive:

\\tcs-trs\shared\2024\LanguageForms\BlankPDFForm\
using (PdfDocument pdf = new PdfDocument(blankPDF)) // I get an error here
{
}

Below is the screen shot of the error:

I am not sure why code is looking for that balnak pdf file on C:\drive when the file actaully resides on the network drive. I am not sure what am I doing wrong. I specified the network path fully in the program.cs file.

Any help will be apprecaited.