Set default pdf import options (options reset on app close)

Thanks for chiming in, I see you throughout the forum. Before responding to your reply, should I just mark the first reply stating "not possible" as the correct answer? Technically it's not possible to set default import options from what I understand. thank you

I was not aware of the pixel limit- which would negatively impact a tertiary task to this one- nor the pdf tool. 

I didn't think of just hard coding the dims into the script... 
Since ppi can be set @300, pixel dims could be predefined to get the desired 3.9inx3.9in doc size. 

Untested code but for many files with static dimensions and static input directory I guess you could do something like this. 1170x1170 = 3.9in @300. Trying to avoid input dialogues:

#target photoshop

// Set the parameters
var parameters = {
    mode: 'RGB Color',
    bits: 8,
    resolution: 300,
    cropTo: 'Bounding Box',
    width: 1170,
    height: 1170,
    pages: 'All pages',
    from: 1,
    to: 1,
    fileType: 'Single File',
    filePath: 'C:/pdfs/files',
    saveToOriginalFolder: false,
    outputFolder: 'C:/output',
    resizeToFit: false,
    resizeWidth: 0,
    resizeHeight: 0,
    action: {
        runAction: false,
        actionSet: '',
        actionName: ''
    },
    fileNameOptions: 'Document Name',
    sequenceStart: 1,
    sequenceLength: 4,
    newFileName: '',
    flattenDocument: false,
    saveOptions: {
        tif: {
            enable: true,
            compression: 'LZW'
        },
        psd: false,
        png: false,
        jpg: false,
        pdf: false,
        saveForWeb: false,
        targa: false,
        printOnly: false
    }
};

// Process PDF files
function processPDF(filePath) {
    // Your PDF processing logic here
    $.writeln("Processing PDF file: " + filePath);
}

// Main function
function main() {
    // Set up parameters and process PDF files
    var pdfFolder = Folder(parameters.filePath);
    var fileList = pdfFolder.getFiles("*.pdf");

    // Iterate over each PDF file
    for (var i = 0; i < fileList.length; i++) {
        var pdfFile = fileList[i];
        processPDF(pdfFile);
    }
}

// Run the main function
main();

Thanks for confirming the dead-end. That is unfortunate.