It was originally supposed to be 3 + 2 years of security updates only, then got bumped to 5 years of full updates when the 6 series reached the end of their 3 year support (I think that was also the time Google first updated the kernel on the Pixels).
Or if you don’t count the initial year, it’s just 6 years for 8+
Or if you don’t count the initial year, it’s just 6 years for 8+