Should be possible - partially. Your maps are a part of Drive so first you need to download desktop Drive client - https://www.google.com/drive/download/ - and enable synchronization. Then you need to setup folder from Google Earth containing maps, to be included or transferred into your Drive synchronization folder. And when done just open your KMZ/KML map in Google Earth, play with it and save it, which will get synchronized with your Drive and your map in MyMaps shall be auto-updated and ready to be edited from MyMaps. then just play with your map on MyMaps and when done it will be auto-updated and auto synchronized with your Drive folder on your PC so its ready to be opened and played again in Google Earth, and so on.