I use GrapheneOs with two users :
1/ Owner user when I start the phone (long password)
2/ Second user when I use the phone (short password for easy unlock)
The phone use File-bases encryption, ok.
If my second user take a photo for example, the photo is encrypted with the master key of the owner user or the second user ?
My real question is, it's more easy to decrypt my files if my second user have a short password ?
(example, dump the full disk and use bruteforcing)