I'm not aware of any working "worldmap zoom changing" addon around.
This addon (outdated and non functional afaik) had a half-zoom option on map open:
https://www.esoui.com/downloads/info...nsTweakIt.html
And this one (outdated as well) was used for the zoom level you like:
https://www.esoui.com/downloads/info...ldMapZoom.html
-> Btw this was found with an easy addon search by using the search term "map zoom" ("map" would have found it too).