Laravel Octane + Nginx proxy within Docker containers

I don't quite understand - is it an anti-pattern to dockerize Laravel applications in production? 95% of the guides I could find on Google are for local setup, which is different from what a production should be (The mounted app volume for starters), the other 5% use some third-party containers. I'm trying to run my Laravel application container, which would serve the app using Octane and then have another container for Nginx, which would act as a reverse proxy. Here is my Dockerfile (I'm quite new to Docker so I'm using the FPM image just because I need bash commands to work and this image seems to enable me to do that).

FROM php:8.0-fpm

# Arguments defined in docker-compose.yml
ARG user
ARG uid

COPY . /var/www

# Install system dependencies
RUN apt-get update && apt-get install -y \
    git \
    curl \
    libpng-dev \
    libonig-dev \
    libxml2-dev \
    zip \
    unzip \
    libz-dev \
    libgd-dev \
    libmemcached-dev \
    memcached \
    libmemcached-tools \
    && apt-get install -y libmagickwand-dev \
    # use pecl to install extensions
    && pecl install imagick \
    && pecl install memcached \
    && pecl install swoole \
    # Enable installed extensions
    && docker-php-ext-enable imagick \
    && docker-php-ext-enable memcached

# Clear cache
RUN apt-get clean && rm -rf /var/lib/apt/lists/*

# Install PHP extensions
RUN docker-php-ext-configure gd --enable-gd --with-freetype --with-jpeg
RUN docker-php-ext-install pdo_mysql mbstring exif pcntl bcmath gd sockets

# Get latest Composer
COPY --from=composer:latest /usr/bin/composer /usr/bin/composer
RUN useradd -G www-data,root -u $uid -d /home/$user $user

# Create system user to run Composer and Artisan Commands
RUN mkdir -p /home/$user/.composer && \
    chown -R $user:$user /home/$user

COPY --chown=$user:$user . /var/www

# Set working directory
WORKDIR /var/www
RUN composer install


USER $user
# RUN echo "0" | php artisan octane:install
ENTRYPOINT ["php", "artisan", "octane:start"]

Here's my docker-compose.yml file

version: "3.7"
services:
  app:
    build:
      args:
        user: usersite
        uid: 1001
      context: ./
      dockerfile: Dockerfile
    image: usersite-api
    container_name: usersite-api
    restart: unless-stopped
    working_dir: /var/www
    volumes:
      - ./docker-compose/php/local.ini:/usr/local/etc/php/conf.d/local.ini
    networks:
      - usersite
  nginx:
    image: nginx:1.25-alpine
    container_name: usersite-api-nginx
    restart: unless-stopped
    depends_on:
      - app
    ports:
      - 81:80
    volumes:
      - ./:/var/www
      - ./docker-compose/nginx:/etc/nginx/conf.d
    networks:
      - usersite

networks:
  usersite:
    driver: bridge

And here's my Nginx.conf file

map $http_upgrade $connection_upgrade {
    default upgrade;
    ''      close;
}

upstream app_container {
    server app:8000;
}
 
server {
    listen 80;
    listen [::]:80;
    server_tokens off;
    root /var/www/public;
 
    index index.php;
 
    charset utf-8;
 
    location /index.php {
        try_files /not_exists @octane;
    }
 
    location / {
        try_files $uri $uri/ @octane;
    }
 
    location = /favicon.ico { access_log off; log_not_found off; }
    location = /robots.txt  { access_log off; log_not_found off; }
 
    access_log off;
    error_log  /var/log/nginx/error.log error;
 
    error_page 404 /index.php;
 
    location @octane {
        set $suffix "";
 
        if ($uri = /index.php) {
            set $suffix ?$query_string;
        }
 
        proxy_http_version 1.1;
        proxy_set_header Host $http_host;
        proxy_set_header Scheme $scheme;
        proxy_set_header SERVER_PORT $server_port;
        proxy_set_header REMOTE_ADDR $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection $connection_upgrade;
 
        proxy_pass http://app_container$suffix;
    }
}

To my understanding, everything is in order. However, when I try to access localhost:81 I get a 502 error from Nginx and when I check Nginx container logs, I see connect() failed (111: Connection refused) while connecting to upstream, client: 192.168.0.1, server: , request: "GET / HTTP/1.1", upstream: "http://192.168.0.2:8000/?", host: "localhost:81"

Perhaps someone could guide me in the right direction?