Hello,
Shutdown option does not serve much of a purpose in Teltonika devices.
The device is designed to operate in exactly this manner, by plugging in/out the power cable, or rather continuously being powered on with periodic reboots for maintenance. It does not even have a physical power on button, dedicated GPIOs or independent services waiting for power on, thus periodic powering of the device would require some external switch or relay.
OpenWrt, upon which Teltonika RutOS is based on, is designed in a way that it performs very few writes to flash, unless you are running some application, specifically configured to perform data writing to flash, any corruption is very unlikely. All the logs are by default stored in device's RAM and are lost upon each device boot, unless configured otherwise.
The SSL issue will be addressed in your other thread.
Best regards,