I had this strange problem before , but i can't remember how to solve it - my computer wakes up by itself from sleep mode. It also happens when another Win10 computer in my home network wakes up.
there are some processes that do that. for example i set my screen to go off after 20 minutes of idle time and it goes off and then after half an hour it turns back on by itself
if you dont want it to wake up from sleep then turn it off completely by shutting down
I have only one Windows 10 PC that wakes itself up to install WindowsUpdates, and none of the Windows or BIOS settings are different from any of the other computers that don't do this. But it is a complicated board with PCIe switch chips.