The users don't seem to mind what's on it. So how should I design one? Are there any methods or good resources for making a good one?
Information that is just displayed, or something to be informed about does not necessarily need a dashboard. This is called reporting.
Something that screams "Action!" is useful as a dashboard. It should help guiding the decision making process.
You might also consider automation. If a machine can do what a dashboard asks for, an action step, then you actually don't need a dashboard instead you can do reporting ("X steps done during Y period").
Build something useful and have fun!
Library: http://www.perceptualedge.com/library.php
You could do a lot worse than becoming familiar with Few's "Information Dashboard Design" book, and the Perceptual Edge blog contains a wealth of material, some of which ended up in his subsequent books.
Older posts on his blog also include reviews of different author's books, often having to do with cognition or analysis related topics which are also informative. Seems he has retired from his consultant business and now blogs at: http://www.stephen-few.com
Here's one of his whitepapers you may find helpful: https://www.perceptualedge.com/articles/Whitepapers/Formatti...
Why are you going to build a dashboard if the users don't seem to need a dashboard?
One suggestion is to use something like hotjar to see how users use the dashboard (once you get something up and running), and analyze what they look for, how they use it, and what they spend a lot of time doing. This might give some ideas on how to make it easier for them to do their jobs. IMO that's the main purpose of a dashboard, so starting there makes sense to me.
If possible (depends on use case / user) give them some level of customization, moving widgets, filters.