Graphene OS may not support Pixel 11 devices due to lack of support for ARM hardware memory tagging:
"We have a partial port of GrapheneOS to the Pixel 11 series after a week of work on it. We're unable to complete the port due to lack of support for ARM hardware memory tagging in software, firmware and near certainly hardware.
It appears Google cut an important security feature to save money.
ARM hardware memory tagging (MTE) is used by GrapheneOS across the entire base OS including the kernel and every standard base OS process. It's only temporarily disabled for a few device-specific processes.
It greatly improves protection against nearly all remote exploits and many local exploits.
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We strongly recommend against buying Pixel 11 devices. Pixel 8, 9 and 10 have much better overall security for GrapheneOS. Pixel 10 is cheaper with similar hardware and MTE. Pixel 11's Titan M3 should improve BFU security for users without a strong passphrase, but losing MTE craters AFU security.
We haven't determined what to do about this situation.
It may be best for us to skip the Pixel 11 series devices. We can shift our focus entirely to the upcoming Motorola devices instead. Pixel 10a was really a 9th gen Pixel, so hopefully the Pixel 11a does the same with 10th gen and includes MTE."