The question we need to answer is: Was the incriminating data planted or not. Having a password manager on his phone is tangental to answer that question. After the computer and phone left his custody, either device could have had data modified. Unless he's got his data pinned into the Bitcoin blockchain, it's a pretty hard to show that it was planted. If it wasn't planted then it's really just about how the key was revealed.
P.S. The description does seem to describe a password manager:
"Specifically, the Cellphone Examination identified various passwords that had been input by the user of the Cellphone to, for example, access the phone, applications on the phone, and/or certain websites."
I think the level of security provided by passwords or password managers is probably of little import, when confronted by a nation-state actor, and indeed a top tier nation-state actor, with nigh unlimited resources, and an axe to grind over a serious grudge.
We have wi-fi routers being used to passively see through walls, with enough fidelity to read lips and record finger movement.
Put someone under a microscope long enough, and every single password they use will reveal itself. Whether locked behind a manager app (sooner or later you'll snag the master password for it) or directly entered.
> We have wi-fi routers being used to passively see through walls, with enough fidelity to read lips and record finger movement.
That’s terrifying. I had no idea that was possible despite it being published years ago and trying to keep track of technology like that: https://ieeexplore.ieee.org/document/7384744/
This is a big blank spot in the complaint, which tells me they broke or got around the encryption somehow. If it was in cleartext they would have said so because it would have added to their case.