Hopefully you don’t have to do this too often. Simplest might be just to use a SOP To DAT and extract the points attributes, now create a second table with a single column called index and fill in the new order. Use a Merge DAT setting the How parameter to “Replace Cells by Column” and use the original SOP To DAT plus your single column Table DAT as the inputs.
Finally use a DAT To SOP on your original geometry and the outcome of the Merge DAT as the Points Table.
Because it is messing up the geometry of the initial grid, you can add a Add SOP and enable “Delete Geometry, Keep Points”. For your case this has no functional impact but nicely hides the otherwise messed up grid geometry.