We (Eimolad) have added only one text variable in JSON format to the backend for ease of operation. In your case, it might look something like this:
type metadata = Text;
metadata = ""metadata": [{"active_players": 10, "unique_players": 3, "name": "eimolad", …},{"active_players": 8, "unique_players":5, "name": "othername", …}, … {} ]";
This way we can easily add or change variables.
In fact, no one can predict the variety of upcoming games and determine the entire list of stats for the future. We use our NFT (EXT standard) as an account access key. The player’s account contains all stats. In different games, players can have different types of stats. Therefore, it would be reasonable to get stats from players’ game accounts, and not from tokens. This does not require any standard of token. Any programming language can easily parse the JSON format.
You can see how we get stats for dwarves from our game accounts on the website: https://ictokens.app/
