Shipping Rule with Quirks

I need to set up a shipping rule that charges a flat fee but I want it to have a few quirks.
1. I need the shipping rule to breakdown as such
• 1-3 items cost $4.00
• 4-6 items cost $5.00
• 7-10 items cost $6.00
• 11 or more shipping is free
2. I'm also selling digital goods where no shipping should be charged

How should I approach this?

when you have a mix of physical and digital goods, you need to create a column in your cart to differentiate them.

Create a new cart column named ProdType.

In the add to cart button, set the ProdType column to 1 for physical items and 0 for digital items.

Now, set up 3 different shipping rules for each of the 3 scenarios where shipping should be applied, for example the first rule will be set up like this:

Trigger:
Number of Items With a Specific Column Value:
If the total Number of items where 'ProdType' has a value of '1' is '>=' a value of '1'

AND
Number of Items With a Specific Column Value:
If the total Number of items where 'ProdType' has a value of '1' is '<=' a value of '3'

Calcualtion:
Flat rate fee of 4