Add entity to mqtt device

let me address your sarcasm, 2 years is nothing for a platform which requires hundreds of configurations and man hours to setup.
I setup my cameras as follows just 2 years ago:

  - platform: mqtt
    command_topic: "cameras_socket"
    state_topic: "cameras_socket/status"
    name: Videocameras
    payload_on: "on"
    payload_off: "off"
    optimistic: true

and now 2 years later (which feels like 2 days considering how many other devices I have set up), I realize the entity is not appearing anymore in home assistant.
And I should re-read the manual because no upgrade procedure has been setup for those who originally started using home assistant some years ago and didn’t keep reading the forum every day.

what is even more odd is that searching google for:

https://www.google.com/search?client=firefox-b-d&q=add+a+entity+to+an+existing+device+in+yaml

returns a question originally asked in 2021: Assign entity to a device

My two cents of feedback: let’s try to keep configuration options as they are and change them gradually in the span of years while keeping an upgrade guide somewhere to reference in the forum: “check the documentation” for people who already read it years ago and need to re-read it completely because everything has been changed is not an answer.