In my projects Docker file I have some environment variables, like this:
ENV ACCEPT_EULA=Y
ENV SA_PASSWORD=Password
ENV MSSQL_PID=Developer
ENV MSSQL_TCP_POR
I suggest to set the environment variables at runtime. If you are deploying to an Azure App Service, app settings are injected into the process as environment variables automatically.
You can then use the same image for multiple environments. With the Deploy Azure App Service task in a release pipeline, you can change the app settings for each environment.
https://docs.microsoft.com/en-us/azure/app-service/configure-custom-container?pivots=container-linux#configure-environment-variables