Traefik 2 Gateway timeout when attempting to proxy to a container that is on two networks - docker

Question

Plenty of questions on this front but they are using a more complex docker-compose.yml than I am, so I fear they may have mis-configurations in their compose file such as this one:
Traefik 2 Gateway Timeout
Within a single docker-compose.yml, I am trying to keep a database container on its own network, an app container on both the database network and the Traefik network, and the Traefik network managed elsewhere by Traefik.
version: '3.9'
services:
wordpress:
image: wordpress:6.1
container_name: dev-wp1
deploy:
resources:
limits:
cpus: '0.50'
memory: 256M
restart: always
environment:
WORDPRESS_DB_HOST: db
WORDPRESS_DB_USER: dev
WORDPRESS_DB_PASSWORD: dev
WORDPRESS_DB_NAME: dev
volumes:
- /opt/container_config/exampledomain.local/wp:/var/www/html
networks:
- traefik-network
- db-network
labels:
- traefik.enable=true
- traefik.http.routers.dev-wp1.rule=Host(`exampledomain.local`)
- traefik.http.routers.dev-wp1.entrypoints=websecure
- traefik.http.routers.dev-wp1.tls=true
db:
image: mariadb:10.10
container_name: dev-db1
deploy:
resources:
limits:
cpus: '0.50'
memory: 256M
restart: always
environment:
MYSQL_DATABASE: dev
MYSQL_USER: dev
MYSQL_PASSWORD: dev
MYSQL_RANDOM_ROOT_PASSWORD: '1'
volumes:
- /opt/container_config/exampledomain.local/db:/var/lib/mysql
networks:
- db-network
networks:
db-network:
name: db-network
traefik-network:
name: traefik-network
external: true
Attempting to hit exampledomain.local fails.
If I eliminate the db-network, and place the database on the traefik network, resolution to exampledomain.local works fine. I do not wish to expose the ports of the wp1 container and would desire traefik to be the only exposed ports on the host. I would prefer not having the db container on the traefik-network. What am I missing?