Both LineageOS and GrapheneOS have this feature, it was extremely useful in the past, until FBE (File Based Encryption) took over from FDE (Full Disk Encryption

Both LineageOS and GrapheneOS have this feature, it was extremely useful in the past, until FBE (File Based Encryption) took over from FDE (Full Disk Encryption). You can't separate the lockscreen password and the startup password anymore, so we lost the usability of unlocking using a shorter scrambled PIN but still retaining a longer passphrase for FDE when the device was powered off. None of this was ever a supported thing, it had to be manually done using `vdc` frontend to `vold` but it was a nice feature.