Função simples pra testar download de arquivo no DRF

gistfile1.txt

# viewsets.py

from rest_framework.decorators import api_view, permission_classes
from django.http import FileResponse
from django.shortcuts import get_object_or_404


@api_view(['GET'])
@permission_classes((IsAuthenticated,))
def download(file):
    """ Função simples para Download de Arquivo """

    arquivo = file
    obj = get_object_or_404(SeuModel, arquivo=arquivo)
    return FileResponse(obj.arquivo)
    

# urls.py

from minhaApp.api.viewsets import download
...
path('media/<str:file>', download, name='download'),
...