Hmm if changing data in a document externally via SQlite, one brute force way to let Grist know that happened is by forcing a “reload”. There is an undocumented but stable endpoint for that. The URL to hit would be:
http(s)://[...however users are reaching grist...]/api/docs/[document ID]/force-reload
and you should POST to it (an empty body is fine). The effect should be for the document to reload for anyone accessing it, and they should see the latest version.
Let me know if that needs more explanation. Document history will be unreliable since it only records changes made by Grist.