Filter Data Table Shows Blank Output

any checks has to be done at the datatable (after read-in e.g. with a read range) as values visualized in EXCEL are not mandatory within the same format / datatype in the DataTable.

Therefore we would use e.g. the immediate panel
Understanding the 6 Debugging Panels of UiPath in the easiest way possible! - News / Tutorials - UiPath Community Forum

Once the details are cleared you can start to develop the LINQ