Not that I am aware, but I have also looked for a way without success. @Stephen_Suen should comment on this.
Yes, it’s tricky, but all you have to do is add a new JSON item after all rows have been added that includes the sums of any specific columns.
The output.table() method is simply exposing the array of JSON item objects and this makes it possible to put also sorts content above, below, and even inside data rows. As such, it’s relatively easy to create aggregations, group-by’s, and averages, etc.
The world (of Airtable) is your oyster.