FP3+, Advanced privacy off, Ecloud sync off.
Yesterday evening: used normally, shut down normally.
This morning: no reaction when trying to turn the phone on by holding the power button. Had to remove-and-put-back the battery for things to go back to normal.
This is the second time I experience this since the 1.0 upgrade, and it never occurred before (got the phone with /e/ preinstalled in November 2020).
Edit: Until now I had not tried taking many photos. Today I experienced the “some attempts at running OpenCamera lead to a black preview” issue.