see the initial answer link for something working via adb (no app UI). guardianproject (fdroid people) made a luks module for android a decade ago. They abandoned the luks approach in favor of IOCipher. You can find a module based on their original LUKS work at https://github.com/aelmahmoudy/cryptsetup-android, try to build this into your rom if you want to develop. Not luks, but people did various ‘userland encrypted containers’ tools, DroidFS in this answer and others.
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