Hi Kalum,
Thanks for contacting Syncfusion Support.
We cannot keep the unsaved changes in midst of the filtering or paging (or any other) actions which is the default behavior of the Grid. Moreover, it is not a valid scenario to keep unsaved changes separately and use them for later. Because, filtering or paging will remove the current data from the DOM and render the new set of records.
In some scenarios, Primarykey for the records will be auto-generated. So, it must be saved prior to any other actions.
Regards,
Seeni Sakthi Kumar S.