Hey there @Scarlet012! You’ve got big plans brewing it seems! It’s definitely good to look ahead. I think it’s a good bet to use a database for large datasets that are going to need to be populated, parsed, and repopulated regularly.
Implementation wise, I’ve had the wonderful pleasure to work with MySQL and SQLite, but never with an API in tandem with UE, so I’ll leave this thread that’s still pretty relevant here and let more knowledgeable answers come through.
Hope this helps, and good luck on your adventure!