Hi @MicroMarc365,
Here is the thing, we only have a form control named EditForm with three modes like New, Edit, View.
Generally, we use NewForm(FormName), EditForm(FormName),ViewForm(FormName) to change the form mode, however we will leave the form mode as Edit by default.
In a word, I don't suggest you set the default mode as New, I suggest you use a button to change the form mode by setting the Button OnSelect property as:
NewForm(FormName);Navigate(FormName)
Then based on your needs, please set the DefaultDate property of the datepicker corresponding field3 as below:
If(IsBlank(TextInput_field2.Text),DatePicker_field1.SelectedDate,DateAdd(DatePicker_field1,Value(TextInput_field2.Text),TimeUnit.Days))