I think what you are looking for is

${DBX_CONTAINER_HOME_PREFIX} or container_home_prefix=…

See also

https://github.com/89luca89/distrobox/blob/main/distrobox-create#L716

I would make a bash function to do this. I’m on my phone so idk how this will look lol

dbxcreate () {
ALL_CONTAINER_HOME=${HOME}/dbx

CONTAINER_NAME="$1"

export DBX_CONTAINER_CUSTOM_HOME="${ALL_CONTAINER_HOME}/${CONTAINER_NAME}"

distrobox create --name "${CONTAINER_NAME}"
}

I would add some checks/more arguments and error messages but thats the idea

You may also have to make that home dir but then its as easy adding a mkdir line