We’re delighted to confirm that this feature is now available 
It consists of two parts:
- Delivery charge structures can now use formulas to calculate the delivery charge amount (see the Formula-based delivery charges help guide)
- Delivery charges can now be applied by the outcome of your delivery rules (see the Delivery rules help guide)
We believe this covers all requested use cases, but if you need anything else, such as new variables available to the delivery charge formula, please do let us know. Cheers.