Can't get Apache rewrite to work on Docker PHP-Apache container

I've followed suit to quite some instructions, tutorials, and also questions in this forum, but I can still not get this working. I've setup a REST API using a PHP Apache Docker container, and need to create a rewrite rule in my apache config to reroute API requests to index.php (the REST controller). Currently, with what's written below, I'm getting a 404:

File Structure on local machine (listed everything except php source code; not needed here):

php
  conf.d
    - error_reporting.ini
    - xdebug.ini
  Dockerfile
  index.php

apache
  - apache2.conf

docker-compose.yml

The content of the Dockerfile being:

FROM php:8.1-apache

WORKDIR /var/www/html/

RUN pecl install xdebug \
    && docker-php-ext-enable xdebug \
    && a2enmod rewrite

COPY . .

EXPOSE 80

And the content of docker-compose.yml being:

services:

  php:
    build: ./php
    depends_on:
      - db
    container_name: php-apache
    ports:
      - 80:80
    volumes:
      - ./php:/var/www/html
      - ./php/conf.d/xdebug.ini:/usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini
      - ./php/conf.d/error_reporting.ini:/usr/local/etc/php/conf.d/error_reporting.ini
      - ./apache/apache2.conf:/etc/apache2/apache2.conf
    environment:
      MARIADB_HOST: localhost
      MARIADB_USER: root
      MARIADB_PASSWORD: top_very_secret
      MARIADB_DB: apidb

  adminer:
    image: adminer
    depends_on:
      - db
    restart: always
    ports:
      - 8080:8080

  db:
    image: mariadb
    container_name: db
    volumes:
      - maria-db-storage:/var/lib/mysql
    environment:
      MARIADB_ROOT_PASSWORD: top_very_secret
      MARIADB_DATABASE: apidb

volumes:
  maria-db-storage:

Regarding the contents of apache2.conf; I've done the following to create it on the local machine:

1. Went into the container's virtual filesystem using docker exec -t -i <container_name> /bin/bash.
2. Wandered to /etc/apache2
3. Printed the file contents via cat apache2.conf
4. Copy-pasted the contents into my local /apache/apache2.conf file
5. Added the following directive lines to the end of that local file:

# Custom directives start here

# Set Server's name
ServerName 'localhost'

# Rewrite for routing of all requests through REST controller
RewriteEngine On

# If requested resource is index.php, do nothing
RewriteRule ^index\.php$ - [L]

# If requested resource is a file or directory that does not exist, reroute to REST 
# controller index.php
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} !-f [OR]
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} !-d
RewriteRule . /index.php [L]

After building the images and running the containers, I've checked within the container's virtual filesystem again via CLI. The /etc/apache2/apache2.conf successfully holds the contents of my local file, and I've also done a apachectl -M within the container, and can see rewrite_module (shared) getting printed.

Again, I'm simply getting a 404; for example if I search for http://localhost/xyz. Same if I do not omit the port (and search for http://localhost:80/xyz). Searching for http://localhost and http://localhost:80 both work; so it seems that my rewrite rules are simply not being applied.

When running apachectl configtest within the docker container, I also get Syntax OK.

Just guessing; does this maybe have something with xdebugs outgoing communication from the container's port 9003?

What am I missing?