I’d recommend reading this post on how to get answers to your questions. I understand you are frustrated, but it is not productive to vent to this degree if you want help.
Since the change happened with an environment update, it’s good to include the output of pip freeze. Since it is in a Docker image, if you can include your Dockerfile (or if the image is public, a link to the image repository itself), that would be helpful to share, if you can. Including more of the log output (especially the output during startup) is helpful, too.
My guess is that jupyterhub was updated, but perhaps jupyter_server and/or jupyterlab are out-of-date. If you want to stick with the classic notebook server, you can set the environment variable:
export JUPYTERHUB_SINGLEUSER_APP='notebook.notebookapp.NotebookApp'