@AndreasHall , we're still working on it.
We've seperated the issues: One is: depending on your computers operating system language settings, Drone2Map is able to pull camare parameters from your images or not. (Drone2Map doesn't support languace settings where a comma instead of a decimal point is the decimal separator - lacking support for non-US-areas of the world has a long history with Esri and seems still not beeing fully addressed).
The other issue is the coordinate system of your project: You need to know what you're doing and the default settings just don't do the job.
We're now at a Z-accuracy level which is within the few centimeter range (z-RMS-error between 0.03 to 0.08 cm; Mean error between 0 and 8 cm). This is acceptable but not great. Basically the accuracy is as good with the M3E RTK and GNSS measured ground control points as it was before when we were using the Phantom 4 without RTK and also with GNSS measerued ground control points.
Upgrading to an RTK-drone (and upgrading image resulution, upgradeing image quality by faster shutter speed and a mechanical shutter) and flying 45° obliques instead of 30° obliques) we had hoped to get significantly better results. So far, this hasn't happened and we're a bit disillusened. We don't know what to next. Is there something we're missing? Should we go with SiteScan or try pix4D or other vendors solutions instead?