@FrostyCat is right, JSON data loaded into a ds_map is a good solution.
Yes, opening and closing an ini file is time consuming if you were doing this in something like a Step Event that runs every frame. That's why loading everything at the start of the game into a ds_map will be optimal.
There are plenty of example posts of loading and saving data to and from a map using JSON on this forum.
I haven't watched this particular tutorial, but here is one example that perfectly matches:
https://forum.yoyogames.com/index.p...ltilingual-via-auto-loading-json-files.57659/
I just used the search box on the forum to search for "json map loading" and this was one of the first results.