Hello @ChrisHeath62,
Can you please check that QuickSight is detecting the fields as Date type? As you can see in my example below, I have 2 date fields but they are not detected by QuickSight, therefore you cannot use them for refreshing the dataset incremetally.
Which should give you the error you are mentioning if you want to setup incremental refresh, you need a dataset where the field types you are going to use for the incremental refresh are of type date, and then, you should see them in the dropdown to be selected.
You can find more information in this community post about datasets and date formats.
Hope this helps!
Kind regards,
Andres.