How to provide a tax rate based on a shipping method (local collection) in Commerce 2?

We must provide a static tax rate to the customer who chooses a specific method (Local Collection). This tax rate would not be based on a customer zone and would replace the zone rates that might exist.

I can get the shipping method from the order and create a new TaxRate object, but I do not know how to integrate the system to force this tax rate when the shipping mode is selected.

I've tried to return the TaxRate object from a custom TaxResolver (extended from TaxRateResolverInterface), but it does not set tax rates for the customer.

Any ideas on how / where to force the application of this tax rate?