Rebuilding Docker images and use existing container configuration

Hi folks,

the following scenario:

I build individual images such as for WordPress myself with a Dockerfile. However, from time to time I have to update the whole thing because the main WordPress image has just been updated. I let Watchtower inform me about this and then execute the command myself:

docker build -t xyz:wordpress --pull /mnt/cache/dockerfiles/wordpress

After that, I have to change something in the configuration file of the container in unRAID each time so that the new image is also used. I would like to automate this. But you can't do something like 

docker build -t xyz:wordpress --pull /mnt/cache/dockerfiles/wordpress && \
docker stop wordpress && \
docker rm wordpress && \
docker run -d --name wordpress xyz:wordpress

as this runs without the configuration of my Docker container from unRAID. Can I access the configuration of unRAID and generate the docker run command from it? Or are there even better ways?