Since downloading drone2map 2023.1 a few months ago I was never able to get my RTK data to project from ellipsoid height to orthometric/geoid heights. The only way to make it work was using ground control, but that defeats the purpose of RTK. I could not make it work despite all my attempts at selecting ellipsoidal Z coordinate systems for my Image coordinates and then using a geoid Z coordinate system for my project.
Come to find out I was doing everything correctly, but missing a crucial program called "ArcGIS Coordinate Systems Data", which you can view in Control Panel-Programs-Programs and Features. If you don't have that program, you need to download it from the ArcGIS Pro section on myESRI.
Thanks to @CodyBenkelman for putting in the time to figure this out.