I want to change shipping cost:
for products in a specific shipping class
basted on quantity range (not per item).
eg:
for 1-4 items (with this class) > shipping= €14
for 5-9 items (with this class) > shipping= €24
for 10+ items (with this class) > shipping= €30
Yes, you can achieve this by using the Shipping Methods by Min/Max Order Quantity module. This module allows you to show shipping methods based on minimum and maximum order quantities.