Error connecting dockerized Django with MySQL on Mac OS

I am using Dockerized Django to connect with MySql but I'm getting the following error:

File "/usr/local/lib/python3.9/site-packages/django/db/backends/mysql/base.py", line 17, in <module>
raise ImproperlyConfigured(
django.core.exceptions.ImproperlyConfigured: Error loading MySQLdb module. 
Did you install mysqlclient?

I also Have tried every single possible solution on stackoverflow and google, but nothing seems to work. I suspect the MySQL driver within the docker container needs to be updated/configured correctly.

Does anyone have any suggestions on what are the exact steps to undertake to fix it? THANKS!

ENVIRONMENT

MacOS 10.15.7.

requirements.txt:

Django==3.1.3
djangorestframework==3.12.2
mysqlclient==2.0.1
django-mysql==3.9
django-cors-headers==3.5.0
pika==1.1.0

Dockerfile:

FROM python:3.9
ENV PYTHONUNBUFFERED 1
WORKDIR /app
COPY requirements.txt /app/requirements.txt
RUN pip install -r requirements.txt
COPY . /app
CMD python manage.py runserver 0.0.0.0:8000

docker-compose.yml:

version: '3.8'
services:
  backend:
      build:
        context: .
        dockerfile: Dockerfile
      ports:
        - 8000:8000
      volumes:
        - .:/app
      depends_on:
        - db
  db:
    image: mysql:5.7.22
    restart: always
    environment:
      MYSQL_DATABASE: !@#$%
      MYSQL_USER: root
      MYSQL_PASSWORD: ******
      MYSQL_ROOT_PASSWORD: ******
    volumes:
      - .dbdata:/var/lib/mysql
    ports:
      - 33066:3306