DNGs do not have edits baked in.
If the proper Lightroom option is turned on (it is not a default), or the proper Lightroom command is issued, your edits are stored within the DNG file as TEXT, and should be interpretable by certain Adobe software.
So, if you did a major LR edit, then saved as a DNG, you could later if you only had the DNG, go back to the original version (unedited)?
Remember. I am developing my original RAW not a DNG, then at the end exporting the DNG.
Lightroom is a non-destructive editor. So, you can take any file type (JPG, RAW, DNG, TIF, other) and edit this photo, and always go back to the unedited version.
If you export your RAW as DNG or export your RAW as "Original", you can also return to the unedited version from the export (but not if you export as JPG or TIF).
With regards to your original statement that you "copied the RAWs to print elsewhere", they may not have had the edits written to XMP. This would also be a problem with DNG, as I said you have to turn on the option to write edits to XMP or issue a command, because by default, Lightroom does not write edits to your DNGs nor to xmp sidecar files for RAWs.
Copying is different than Exporting.
First of all, DNG is not like a PDF. DNG is an alternative raw file format developed by Adobe to standardize where information is stored. When a DNG file is created all of the raw image data from the original raw file is copied into this new container. As a benefit, you have all the raw editing capabilities using a common file format.
In its default state, Lightroom does not write any changes to any image. This is true regardless of the file format. There is an option you can choose that will write changes to XMP. When that is selected, changes made in Lightroom are written to XMP files for original raw file formats. In other formats, including DNG, those changes get written into the header area of the files.
When the reset button is activated on any image that has been edited using Lightroom, the image will Be restored to its default state, as it was when it was first imported into Lightroom. And you can do that regardless of whether you are working with the original raw file or with a DNG copy.
Everyone has their own way of working with Lightroom. I don't automatically write changes to XMP files. I prefer to depend on the catalog to keep track of the work I have done. I export copies when I need them to share with others or to send to a lab, but they are discarded as soon as they have been used for their intended purpose.