Currently, the 100W car charger Cypress can offer is CY4532 board. Download link: https://www.cypress.com/documentation/development-kitsboards/cy4532-ez-pd-ccg3pa-evaluation-kit
If you have a chance to take a look Cypress AUTO Car Charger solution, you will get 100W car charger solution directly: https://www.cypress.com/documentation/reference-designs/ez-pd-ccg3pa-automotive-2x100w-charge-only-reference-design-mps
From the reference design, you will see that the 100W support limitation is on DC/DC side. CCG3PA just need configuration and VCONN support is enough.
For change CCG3PA Car Charger reference design to CCG3, we do not recommend it. Since the reference design you have been figured out is based on directly feedback and relay on FB of CCG3PA. If you change to CCG3, you have to use I2C control DC/DC and the PPS support becomes high risk.
Where do I find the Cypress AUTO Car Charger solution? I've reached out to several of the distributors on your list and none of them have it. Is it an actual product or is it just a reference design?