In this tutorial we export a google image and kml file from Google Earth Pro. The kml layer is then used in QGIS as the control points in georeferencing the image in QGIS.
Great tutorial - it worked! Then saved geotiff file in QGIS to import into Avenza Maps app to use out in the field. Key was changing the icons to get enable accurate georeferencing of control points.
It could be a bug in the program. I would suggest uninstalling 3.12 and installing 3.10 instead. 3.10 is the latest most stable LTR version of the application.
All worked for me until the final bit and my points were all west of where I wanted them. I couldn’t find the snapping option- am on Hannover version - they must be elsewhere as there wasn’t a snapping options just options.