Don't make it harder than it is. A privacy screen runs for $10 and graphene and other OSs have option to scramble pin input layout so there is no order to capture.
The more difficult it is the less likely you are going to do it.
Discussion
i personally just carry a day phone that has nothing on it, no personal photos, only data the agencies already have anyhow and work stuff. factory reset every once in a while.
but i see your point.
There is no one size fits all. Your strategy should fit your threat model. I just want people to think through what that would be and not just accept the default.
yeah my threat model is 1) someone snatching the phone while unlocked 2) some retarded gov agency forcing me to unlock and clone the entire phone for some retarded reason cause they can.
this mitigates fallout in both cases.