but there is a reason i just explained it to you

Ok but is there room for the idea that your intuitions are incorrect? Plenty of things in the world are counter-intuitive. ‘docker-compose up -d’ works the same whether it’s one container or fifty.

Computer resources are measured in bits and clock cycles, not the number of containers and volumes. It’s entirely possible (even likely) that an all-in-one container will be more resource-heavy than the same services split across multiple containers. Logging from an all-in-one will be a jumbled mess, troubleshooting issues or making changes will be annoying, it’s worse in every way except the length of output from ‘docker ps’

I can see why editing config files is annoying, but why exactly are two services and volumes in a docker-compose file any more difficult to manage than one?

I disagree with pretty much all of this, you are trading maintainability and security for easy setup. Providing a docker-compose file accomplishes the same thing without the sacrifice

• separate volumes for configuration, data, and cache because I might want to put them in different places and use different backup strategies. Config and db on SSD, large data on spinning rust, for example.
• separate container for the database because the official database images are guaranteed to be better maintained than whatever every random project includes in their image
• separate networks because putting your reverse proxy on a different network from your database is just prudent