The car rental insurance information for the various Amex cards can be found at https://www.americanexpress.com/us/...tal-loss-and-damage-insurance-terms.html

Most credit card rental insurance is Secondary, meaning that you have to first file with your personal car insurance company, but some are Primary.

Amex also offers a premium car rental insurance plan, which is fee-based, a fee per rental, not a fee per day. https://feeservices.americanexpress.com/premium/car-rental-insurance-coverage/home.do

The Points Guy has written about some cards which include car rental insurance. https://thepointsguy.com/guide/cards-primary-car-rental-coverage/