I only have a moment to respond, so this will be short but sweet!
Airpress doesn’t (currently) interact with a page/posts REAL custom fields. Remote Airtable data is fetched when the page/post is loaded based on your configuration settings and/or code. So rather than WordPress being “updated” when Airtable data changes, think of it as WordPress “fetches” required data when a page/post loads.
If you want to fetch remote Airtable data when a post is EDITED or CREATED that is a different task. I’ve thought of building a “Custom Fields Sync” module, but I can’t honestly think of a use-case where my existing functionality wouldn’t satisfy.
I’d love to heard a little more about why you want WordPress Custom Fields populated with Airtable data rather than accessing that data in “real-time”.
If there’s a use case I’m missing, I’d love to expand Airpress to cover it. Let me know! And thanks for the kind words and feedback.