The Mavic 2’s can’t shoot Raw Only. It’s JPEG only or JPEG & Raw. The preview images produced will come from the JPEG version and will always differ from the Raw image - usually a little sharper and more saturated.
So much noise from a Raw or JPEG looks worse than I would have expected but noise in shadow/low light areas is normal.
If you can post one of the DNG images we could check further for you.
The M2 will do raw only:
We are definitely not looking at the JPEG preview of a raw image, because that is much lower resolution.