Moving color palettes from template files

I was disappointed when Numbers recently started using highly saturated colors in the Fill Color swatches (they used to be more pastel). I save pastel colors in my own swatches in the Colors dialog, but they are more time consuming to apply that Numbers' own Fill dropdown menu.

I notice that some templates (such as Business > Invoices and the Meal Planner) each have a different selection of colors in the color palettes, and the top row are more useful (pale) colors suitable for headings with black text.

Is there any way to export or move color palettes between documents? Or any way to make the Invoices colors the "default"?

I was able to delete the Invoice data*, save it as a "blank" file, then copy and paste my own spreadsheets into the blank file. Now I have useful colors in the Fill menu! And I can use this blank file for a template going forward. Is this the only way?

Would love a way to import, export and save color palettes from the templates. Or at least change the default settings. (similar to Photoshop etc.)

(* If you want to do this, you need to right-click on the blue bars in the Invoice and select Unlock, then you can delete those elements.)