Supervisord breaking Laravel application

I have a laravel 9 application that I want to deploy to AWS ECS. The application uses redis for queue and I have installed horizon. I also installed Supervisor in the docker container but once I deploy my application and start up supervisor in my startup.sh script, my app is never reachable and I notice that both queue worker and horizon start and then exit.

Here's the dockerfile I am working with

FROM php:8.1.4-fpm-alpine3.14

RUN apk update

RUN apk add --no-cache git libzip-dev zip unzip php8-exif supervisor

RUN mkdir -p /usr/src/php/ext/redis; \
    curl -fsSL https://pecl.php.net/get/redis --ipv4 | tar xvz -C "/usr/src/php/ext/redis" --strip 1; \
    docker-php-ext-install redis;

RUN docker-php-ext-configure pcntl --enable-pcntl \
    && docker-php-ext-install \
    pcntl

RUN docker-php-ext-install pdo pdo_mysql zip exif \
    && curl -sS https://getcomposer.org/installer | php -- \
    --install-dir=/usr/local/bin --filename=composer

WORKDIR /var/www/html

COPY supervisord.conf /etc/supervisor/conf.d/supervisord.conf

COPY . .

RUN chown -R www-data:www-data /var/www/html

RUN composer install --ignore-platform-req=ext-pcntl

RUN chmod 544 startup.sh

ENTRYPOINT ["./startup.sh"]

this is my supervisord.conf file content

[supervisord]
nodaemon=true
loglevel=debug
logfile=/var/www/html/storage/logs/supervisord.log
user=root

[program:laravel-worker]
process_name=%(program_name)s_%(process_num)02d
command=php /var/www/html/artisan queue:work redis --sleep=3 --tries=3 --max-time=3600
autostart=true
autorestart=true
stopasgroup=true
killasgroup=true
user=root
numprocs=8
redirect_stderr=true
stdout_logfile=/var/www/html/storage/logs/worker.log
stopwaitsecs=3600

[program:horizon]
process_name=%(program_name)s
command=php /var/www/html/artisan horizon
autostart=true
autorestart=true
user=root
redirect_stderr=true
stdout_logfile=/var/www/html/storage/logs/horizon.log
stopwaitsecs=3600

and my startup.sh script content is

#!/bin/sh

/usr/bin/supervisord

php artisan migrate
php artisan db:seed

php artisan config:cache
php artisan route:cache

php artisan serve --host=0.0.0.0 --port 80

If I comment out /usr/bin/supervisord and deploy to aws ecs, I am able to reach my app again. So what exactly am I doing wrong with the supervisor that is causing it to break my app and how can I fix it?