The only way I can think of ( and this assumes you can export the Google My Maps data to a CSV file, and it includes the coordinates ) is to use a this plugin.
If you don’t have the coordinates, but only the address details, then you can use the CSV Manager add-on. This will geocode the coordinates on import.
Thanks. I’ll look into that. Unfortunately, Google Maps does a really poor job of geocoding based on address in the country this is being developed for, so the CSV Manager plugin won’t help if the long/lat info is missing. The ability to manually reposition the map marker was one of the major reasons I chose your plugin–that, and your excellent response history on support threads like this. Glad to see that is still true.