hi
my phone reboots almost every time in selected locations with 3g mode activated. if 2f or 4g mode is forced - works perfectly. unfortunately no voice-over-lte is supported, so i should choose - either calls or data.
seems to me as buggy modem driver - no "user" app should crash kernel
i've "almost the same" problem with my blackberry priv - it reboots "on it's own". the only difference - it's reboots "back to normal" - no "unlock password" required
and yes. assuming no updates since aug 2020 - seems it's already dead.