The other day I asked for an analysis or at least an UML diagram since we are having quite some troubles and my boss looked disgusted at me for asking such a question. I’m not a professional backend developer, so I don’t know how it works professionally
I haven’t made a UML diagram in years. Or an ER diagram, for that matter.
Getting a schema dump and/or generating a diagram from an existing system would be useful, it won’t be UML, but can convey similar information. At a certain point, keeping an updated UML diagram is extra work that is almost guaranteed to go out of data instantly.