Along with the aforementioned comment, I would like to add the following points for further consideration.

The Google Sheets Tables feature is a new addition to Google Sheets. However, this feature is not currently compatible with Google Apps Script or the Sheets API. Therefore, Google Apps Script cannot be used to retrieve Google Sheets' Tables.

There are two related pending Issue Tracker posts that are feature requests related to this post.

The first one is “Programmatic Access to Google Sheets Tables”

Which states:

Tables in sheets cannot be manipulated via the API: it would be great to be able to rename Google Sheets tables (or change any of their other attributes) via Apps script, but I could not find any service or class allowing me to do so.

And, the second one is “Add table management methods to the Spreadsheet service in Apps Script.”

Which states:

For instance, consider adding a getTables method to the Spreadsheet or Sheet class. This method could:

• Retrieve all tables as class objects.
• Provide class objects with methods for retrieving and setting table names, ranges, and other properties.

As of now, there are currently 8 people impacted by this feature request and 42 people impacted by this another feature request. I suggest hitting the +1 button for these two related feature requests to signify that you also have the same issue and consider adding a star (on the top left) so Google developers will prioritize/update the issue.

There are also related posts published on this in the Google Cloud - Community. One is titled “Workaround: Using Google Sheets Tables with Google Apps Script”.

This report proposes a workaround solution using Apps Script until native support arrives.

You may consider it; it might suit your needs.