Can I use the Qualtrics API to upload a PDF file to a individual survey response

I am building a small server that converts html files to pdfs and then sends a download link to qualtrics where I am able to use custom js from within my survey to click the link which then automatically downloads the pdf to a respondent's machine. I would like to upload the pdf from my server to the respondent's data, but can not find a method or API possibility for doing this. I've tried using the route below to send my pdf and am getting a 200 but there is no file there. If I can successfully upload a pdf file to a respondent's data my goal is to then have a workflow setup that sends a link to the pdf which is stored on Qualtrics to the respondent, which I know is possible from tests with upload questions. I've searched extensively through the API and can't find a method for uploading a pdf file to specific response. There isn't a method I could find for uploading a pdf using the libraries or files methods either. Any help is much appreciated. Thank you.

@app.route('/upload', methods=['POST'])
@cross_origin(origin="{QUALTRICS_URL}")
def upload_pdf():

data = request.get_json()
response_id = data['responseID']
qualtrics_key = constants.QUALTRICS_API_TOKEN
QUALTRICS_URL = 'blanking this field for privacy'
SURVEY_ID = my_survey_id
url = f'https://{QUALTRICS_URL}/API/v3/surveys/{SURVEY_ID}/responses/{response_id}/files'
headers = {
'content-type': 'application/json',
'x-api-token': qualtrics_key
}

with open("test.pdf", 'rb') as pdf_file:
files = {'file': pdf_file}
response = requests.post(url, headers=headers, files=files)
if response.status_code == 200:
print(response)
return 'File successfully uploaded'
else:
return f'Error uploading file. Status code: {response.status_code}. Error: {response.json()["meta"]["error"]}'