Let's address the first problem first - the random rebooting.
Some random reboots are caused by third-party apps. Boot your device into Safe Mode to temporarily and safely disable all third-party elements. In Safe Mode, if the device does NOT restart, then it is definitely a third-party app causing the issue.
If it does restart, then delete the system cache. Boot into Recovery Mode and select Format Cache Partition. Reboot and test.
If these do not fix the restart issue, then be mindful of the LAST app open when the restart occurred. It could be that app.
If all else fails, unfortunately, you will need to back up your data and perform a factory reset to rule out if it is hardware failure or firmware issue.
Second, the time issue. This could also be caused by same app causing restart, but let's check some settings first.
Most times it is that the Automatic Date/Time Setting got corrupted. It happens. To check this... Go to Settings, then to System, then to Date & Time. Select the button next to Set Time Automatically to trigger it. If it is already turned on, then turn it off, restart your phone and then turn it back on.
Most applications depend on date and time, so if that is wrong, the app won't work.
Yes, any security updates will be included in the factory reset, but still check for updates after reset, to be sure.
Also, after the factory reset, if you do that, check the Google Play System Update to make sure that got updated also. Go to Settings, then About Phone, and click on Google Play System Update. That will check for system updates to the Google Play code.
After turning off the automatic Date/ Time, restarting the phone and turning it back on it seems to not change the date anymore. I also shut off auto optimization and so far so good. Thank you again for the advice. Much appreciated
