I used to be bullish on creating ERDs, often using them as an onboarding exercise, even for databases with 100+ tables. However, comprehensive ERDs are becoming rare, and that's okay. Their value is short-lived due to the high cost of maintenance. While polished ERDs can be nice to have, they aren't essential.
For creating ERDs as code, tools like dbdiagram.io and eraser.io are popular options. ERWin is the original tool for UML/ERD diagrams, but it's expensive.
hand creating these seems like a mistake, i.e, like you said hard to maintain. In my opinion every database should generate (or have a tool) to generate diagrams automatically.
For creating ERDs as code, tools like dbdiagram.io and eraser.io are popular options. ERWin is the original tool for UML/ERD diagrams, but it's expensive.