See their list of device requirements: https://grapheneos.org/faq#future-devices
Relevant discussion of Kagi and Wolfram (2024): https://news.ycombinator.com/item?id=39606048
As heard on KPBJ: https://news.ycombinator.com/item?id=47052674
Previous discussion (2018): https://news.ycombinator.com/item?id=17376753