Hey @richklau,
you should not choose “Children” as the property of the table. You will indeed have to do two callbacks, one for the columns, and one for the data.
I answered the same question a couple of weeks ago. You will have a concrete example with a date picker as well :
https://community.plotly.com/t/datepickerrange-to-update-data-table/16193/5?u=qdumont
I hope this will help you,
Quentin