I want to delete the file of the respondents uploaded by the Google form upload function after submitting the form.

I am currently thinking of using the upload function in Google form.

First of all, regarding the specifications of the Google form,

at the time the respondent uploaded the file before submission The respondent's owner's file will be saved to the respondent's drive (just below).

Submitting the form afterwards

in the file storage location on the drive on the form creator side The form creator saves the owner's upload file.

So, at this rate,
Respondents consciously submit the form
You have to erase the uploaded file directly under your drive
Upload files will continue to accumulate directly below the drive.
Using GAS or other means (if any) somehow
We would like to delete the respondent's upload file after submitting the form.

Currently, referring to the Internet and books, the form GAS is as follows:
I am writing a program to get answers and send emails.

function noticeFileUpload(e){
    varitemResponses=e.response.getItemResponses();

    for (vari=0;i<itemResponses.length;i++) { 
        variableResponse=itemResponses[i]; 
        varquestion=itemResponse.getItem().getTitle(); 
        var answer = itemResponse.getResponse();

        Logger.log(question);
        Logger.log(answer);

        if(question=="submission document"){
            varfileId=answer;
            varfile=DriveApp.getFileById(fileId);

            var address = 'email address'; 
            US>vartitle='[Google Form Send Test] File Uploaded'; 
            var content=' file uploaded successfully.\n\n'
            + US>'File Name:'+file.getName()
            + US>'\n\n'
            + *This is an automated email sent from Google form.'; 

            GmailApp.sendEmail(address, title, content);
        }
    }
}

In this way, I know the code to get the answer, but
I don't know the specific code to retrieve the files that the respondents uploaded to their drive.

Delete the automatically appended account name from the file name saved in the answer. Do I have to search for a file with the same name directly under the drive → delete them?
(In that case, I am also concerned about how to deal with files with the same name if they already exist.)

I'm sorry, but I'd appreciate it if you could tell me.
Thank you for your cooperation.