Yeah, again I would expect that the newest version of CarPlay will be available in your vehicle as soon as (1) Apple releases iOS 26 and (2) you install it on your iPhone. And I am pretty confident that Apple will release iOS 26 when they said they will, given that timing is usually aligned with their new iPhone launch.
Now, as for the Apple Wallet car key support, not sure. I see what you mentioned, that Apple has announced that a number of new vehicle brands will be gaining car key support, including Chevy/GMC/Caddy. Looks like it’s unclear as to when and which models.