In the latest release of GrapheneOS, you can now enable hardware memory tagging for all user installed apps on the Pixel 8 and Pixel 8 Pro to make them substantially harder to exploit. This is particularly useful for apps like Signal and WhatsApp.
https://nitter.net/GrapheneOS/status/1728907796954124656#m
We mentioned Signal/WhatsApp because despite having end-to-end encryption, they both have a massive amount of remote attack surface, use tons of memory unsafe code for handling media, voice/video calls, etc. along with not using sandboxing. E2EE does no good if app is exploited.