Carlos,
I've got a Fenix 6 pro as well. In the map menu, the default maps are labeled:
"TopoActive NA, US 2024.20"
"TopoActive NA, Canada/Alaska 2024.20"
"TopoActive NA, Middle America 2024.20"
These follow the same naming and part number format as the South America map from Garmin. Assuming the available file is a copy of the official one from Garmin, you can verify that it does work with our Fenix 6 watches by looking at the "supported devices" section here:
[Please Register or Login to download file] After downloading the linked file, extracting the disk image via RAR, and placing it in the "GARMIN" folder on the watch. Upon disconnect, the watch reads "loading maps" followed by a pop-up "Cannot authenticate maps. Contact the map content seller for help." The map doesn't show up when I visit the list of available maps by Settings→Activities and Apps→Map→Map Settings→Map→Configure Maps.
I tried renaming the file to "gpsmapsup4" and restarting the watch, but no luck. I'm going to leave this issue be for now, and try to load the openstreetmap ones instead. Hope this helps.