We also extended it to the pogo pins on the Pixel Tablet. It's one of our official hardware requirements (https://grapheneos.org/faq#future-devices) and we expect it could be implemented for Snapdragon too but it's missing hardware memory tagging and devices using it are missing far more...
We've heard that iOS 18.1 is using a 4 day timer for auto-reboot after the device is locked, which is similar to the 72h default we used before moving to an 18h default. Our users can configure it between 10 minutes and 72 hours (or disabled) based on their tolerance for it.