How to update Images with custom XMP data to replicate Phantom 4 Pro RTK images ?

The new P4 Pro RTK adds the following tags to the metadata.
(With sample data from an RTK photo)

Rtk Flag                        : 16
Rtk Std Lon                     : 2.70368
Rtk Std Lat                     : 1.53912
Rtk Std Hgt                     : 3.68277

I have an external Emlid Reach M+ GPS on my regular phantom 4 Pro.  I am post processing the flight data and events in EZsurv.  I export the data shown above for all images into a CSV file and  I need to import that into the metadata of the images.   Then they will be processed just like the P4P RTK images.

My problem has been finding an EXIF editor that I can figure out to import these XMP tags into the images.  My CSV file will contain

Image File name
Post Processed Lat
Post Processed Lon
Post Processed Alt

Lat Standard Deviation
Lon Standard Deviation
Alt Standard Deviation

For the updated GPS data, I will simply overwrite the coordinates currently in the EXIF data.  Then I need to add the new XMP tag data for the Standard Deviation.

Any help on the best program to use and how to do it will be appreciated.  I have played around with multiple exif editors and so far I have not found one where I can successfully add the custom data.    There was a thread on the agisoft forum that is similar so if I find a solution from there I will just post back here with an update.  

Thanks!