Is it possible to somehow understand from the logs what happened to the phone a month ago? Are there such logs?
Here is some ADB commands that can help:
Dump each app and it data usage
for package in $(pm list packages | cut -f2 -d&quot;:&quot;); do echo $package; pm dump $package | grep  &quot;Mobile network&quot;; done;

Monitor Application
for package in $(dumpsys package | grep &quot;Package \[&quot; | cut -d &quot;\[&quot; -f2 | cut -d &quot;\]&quot; -f1); do
    echo $package $(dumpsys package $package | grep firstInstallTime)
done;

That will list install date of all the applications on the device.
You can replace &quot;firstInstallTime&quot; with &quot;lastUpdateTime&quot; to get last update time.
Some applications monitor and store the phone state in a database or a log file, you can also backup the apps in the device and try to find some useful information in these backups.
Hope it can help!