Adding Product Installation fee option to store (for customers within 30 miles)

[NagartHUN]

Hello there! I am creating a store for a client, and would be curious if anyone has a solution for the following problem.

Client sells solar energy storage units, and also offers installation services for clients at X price if they ask for that and they are located near their operations.

In the beginning they only want to offer this installation service for clients who are 30 miles away from their location (or future locations/certified installers) - I know local delivery function allows range-based limitation, but how could I add the service at X price and make only customers near the location able to pick the installation option? Where would they be able to pick this option?

Later on, they want to roll-out installation without range limits, so the question then would be, what's the best way to go about adding a "Request Installation +X $" type of fee to the store?

Thanks in advance for any input!