ahhh I wish GrapheneOS was supported on these!
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This comparison is pretty damning: https://eylenburg.github.io/android_comparison.htm
Calyx is _not_ a hardened OS, and runs on devices with insecure hardware and firmware (like a Fairphone). Additionally, app compatibility suffers because they use microG instead of proper sandboxed Gapps, and also lacks many QoL features that guard against hostile apps (storage scopes, contact scopes, ...).