Computer Self-Wakes From Sleep

Problem

I put the computer to sleep, and at some point, usually quite quickly, it wakes itself up again.

Solution

There is a good chance that your PC's Network Adapter is waking it. This is a Power & Sleep issue.

You may disable this ability by locating your PC's Network Adapter in Device Manager and opening the Properties window. Then, click the Power Management tab and uncheck the box for "Allow this device to wake the computer".

Solution

To keep your computer from waking up in sleep mode, go to Power & Sleep Settings. Then click Additional power settings > Change plan settings > Change advanced power settings and disable Allow wake timers under Sleep.

Source

https://docs.microsoft.com/en-us/answers/questions/189406/windows-10-waking-up-from-sleep-on-its-own.html