You are right that the range is wide. You need to figure what are good values to have for your category. Also, you can focus on the trend (is your DAU/MAU increasing vs decreasing after you make changes) even if benchmarking is tough.

Unless your app is adding a huge number of users every day (which can skew DAU/MAU), you can trust the ratio as a good indication of how engaged your users are.

For games, DAU/MAU of ~20-30% is considered to be pretty good.

For social apps, like a messenger app, a successful one would have a DAU/MAU closer to 50%.

In general most apps struggle to get to DAU/MAU of 20% or more.

Make sure you have the right definition of who is an active user for your app, and get a good sense of what % of users are actually using your app every day.

Happy to discuss what is a good benchmark for your specific app depending on what it does.