To set up auto restart, go to settings>device care>auto optimization>then toggle on. I dont believe that you can choose exactly when it restarts though. However, it does say that it will restart at times where you aren't using your device.
I'm curious why they removed the feature to restart when I decide to. Frankly, I believe that this wasn't thought out and should be placed back as soon as possible. There's no reason for me not to be able to restart my phone at the exact moment I deem it necessary. Furthermore, for people who have to wake up in the morning this could stop their clock and it won't ring during a restart or even until the phone is unlocked. That means if I fall asleep at 12am, my phone restarts at 1am, and I have an alarm for 6am, then I will not hear it. I strongly suggest that this gets fixed because it is foolish to be straightforward.
