Grey out unexplored maps
There are areas in the game with no points of interest or even waypoints, but they do count for the achievement. Sometimes it’ll be a cave but the cave’s name shows on the map and that may count as well. So make sure that all areas in white lettering shows up on your map, consult Wiki or compare with a friend. When I did my first I discovered 5 more areas even if my 30 maps were completed.
You can easily just cross reference the names of zones to the wiki page.
It’s already pretty doable.
I had to use wiki to get the last 3 areas. You just have to compare your big map with the names in wiki. It’s a little tedious but doable.
Thanks for the tips. It was a bit annoying, but using the wiki I went thru each zone one by one, and found areas listed in the wiki that had no poi’s or waypoints, or hearts, then cross referenced with my map. That did the trick