No, only 1 map in the Game Instance.
There is no limit to how many elements a Map can store (there is but that’s a big number). Map consists of Key | Value pairs. The key must be unique. If you add the same key again, the value gets replaced:
This seems to be perfect for this. You do not need to populate anything in advance - simply start adding level names and their structs to the map as you play.
If the entry does not exist, it will be created. If it does exist, its value will be replaced.
And, most importantly, you do not need to look up anything (you would with an array if you replay level 5 and you have 10 levels); and you will not get any duplicates this way - since Map keys must be unique.