I am admittedly confused by Garmin's approach to maps so I may not be giving you the best information. Garmin used to have something called regional Cycle Maps, one of which came pre-loaded on your device based on your region. If you wanted maps for different regions, you had to purchase them from Garmin.
In May 2025, Garmin discontinued Cycle Maps and replaced them with TopoActive Maps, which seem to sell for USD 59.99 (imagine having to pay for the Greenland map).
https://www.garmin.com/en-US/p/730831/My guess is that you still have to pay for maps that didn't come pre-loaded on your device, but that may have changed with the switch to TopoActive - I don't know.
Having said that, kind people on the interwebs have made available free Garmin maps; these work well enough but require some tinkering to install.
https://garmin.bbbike.org(If you're really technically-minded, you can even take raw OpenStreetMap data and convert it into Garmin maps but that's not for the faint of heart.)