Edit: last released leak showed they had broken the then most recent iOS release (17.5.1) in AFU state on all but the most recent hardware which was marked "available in CAS"
https://discuss.grapheneos.org/d/14344-cellebrite-premium-ju...
The good news is neither pixel nor iOS seems to show full file system extract under BFU state in the recent tables I can find.
GrapheneOS has access to the latest Cellebrite Premium documentation since we have a contact able to share it with us. In April 2024 and then July 2024, we posted screenshots of specific capability tables from the documentation but then stopped doing it because it could result in losing access to it. The contact sharing it with us was still fine with us doing it but later came to the same conclusion we did that it's best not to post anything from it. Cellebrite doesn't like it being posted publicly even though it's essentially marketing their products, probably because it results in pressure on Android and iOS to stop it happening.
Apple and Google do not appear to have a regular source for finding out which vulnerabilities are currently being exploited. Both appear to be refraining from actively seeking our these devices to patch all the exploits they use. It's often external researchers including at Citizen Lab and Amnesty International determining which vulnerabilities are being exploited by these tools and reporting it to both Apple and Google. Long periods of time often pass with no loss of capabilities for new Android and iOS versions. The main reason Cellebrite loses access is likely tied to the deployment of new exploit protections requiring working around those and using new vulnerabilities. Code churn also likely impacts them.
You seem to be mixing up what they're referring to as a BFU exploit with a BF exploit. Pixel 2, Pixel 6+ and iPhone 12+ have withstood Cellebrite's efforts to do brute force attacks against a BFU device. BFU exploit means they can extract data such as saved Wi-Fi networks and installed apps, but without a BF exploit they cannot bypass the secure element throttling. It may become impractical for them to have BF exploits anymore, but it doesn't make their BFU exploits worthless.
Apps are installed so that their packages are available before first unlock and can explicitly opt-in to supporting a specific subset of their components and data before available before first unlock. An app can implement push notifications before first unlock if the developers want to do it, and they could do that in a way where no message data, etc. is available before first unlock. The OS leaves it up to apps to decide what to do, and nearly all apps stick with the default of all their functionality and data available After First Unlock instead of either making it available Before First Unlock or having it go back at rest while locked again.