Have you considered seeing what comes up on britishairways.com>book>"hire a car" for your destination? Inclusion of "Third Party Liability (TPL)" and "Collision Damage Waiver" isn't unusual there. May be worth looking into for your situation.

While there are states where there is some state requirement for the rental car company to have some basic liability insurance coverage for its vehicles, that state-required liability insurance coverage on US rental vehicles is often so little as to be insufficient when the renter really need the coverage to deliver materially. And I wouldn't be surprised if the car rental companies may reserve the right to come after the renter for the liability costs incurred anyway, even when its liability incurred under the amount of coverage required by state law/regulations applicable to the rental car company and their vehicles (under any "basic" liability requirement under state law).

The UK Amex Platinum: