Frequently your Grid Data will arrive AFTER the grid has rendered.
This can be handled in ag-Grid GridOptions directly and then everything will flow through.
However AdapTable provides the loadGridData function in Grid Api which is designed for this precise use case (for subsequent refreshes you can use setGridData).
The function will load the data in the grid and then make sure that anything that is dependent on that data load will also run (e.g. includeExpandedRowGroups).
This demo loads the data 3 seconds after the grid is initialised - and adds the Format Columns to 'Invoiced Cost' and 'Order Date' columns.
Then after another 3 seconds it adds 2 extra columns - 'Package Cost' and 'Company' - which AdapTable handles very smoothly.