How would I get a primary button to render as a top button for the dialog

[RiceDam]

Currently, I have this prop for the top buttons in the dialog:
topButtonsProps: [ { buttonType: ButtonType.default, keyType: 'Save', iconProps: { iconName: 'Save', }, text: 'Save', primary: true, type: 'submit', }, ],
All it shows is the icon at the moment.