Update: I swear that when I answered there were no other answers! I must have been blind. Sorry, this post doesn’t add much to the discussion.
This wiki has over 32K tiddlers, with no noticeable slowdown. I would suggest that it’s simply worth trying. You could just import the above if you converted slightly:
{
"title": "A Realm Reborn",
"tags": "MtgCard",
"image_uris.normal": "https://cards.scryfall.io/normal/front/d/1/d1af74e4-38d5-44b5-85e1-4d13f6970453.jpg?1748706495",
"mana_cost": "{4}{G}{G}",
"type_line": "Enchantment",
"legalities.commander": "legal",
"set_name": "Final Fantasy"
}
That is, change name to title and add a tags parameter to identify the sort of data involved. The tag makes it much easier to query, but is not required. title is required; it’s the unique key. If any of these names are likely to conflict with other tiddler titles you want to have, then you can add a common prefix, such as Card/A Realm Reborn, in which case, you might also want caption: A Realm Reborn to have the familiar title in lists.
(I would also suggest normalizing the field names to using a single separator. But only for cleanliness; it’s not essential, and it won’t hurt anything to have image_uris.normal, but it can get difficult to remember. Most peoples settle on kebab case or snake case, but anything will do, so long as there are no spaces.)
If this doesn’t slow things down, and I don’t think it will, then you should find that querying your data is much easier than it would be in JSON. You can see in a current thread that there are discussions about how to make it easier to query JSON tiddlers, and you’ll see me arguing that it might not be worth doing. Right now JSON data is definitely a second-class citizen in TW, and there’s a very good chance that this will long remain so.