Windows 10 keeps waking up from sleep on its own – no idea what's causing it

I put my Windows 10 PC to sleep before going to bed, and every morning I wake up to find it running. Sometimes it wakes up within an hour, sometimes after a few hours—no pattern I can figure out.

I've already checked the usual culprits:

Ran powercfg -lastwake – shows "Unknown" or "Wake Source: Device"

Disabled wake timers

Turned off "Allow this device to wake the computer" for my mouse, keyboard, and network adapter

Still happens. I'm not sure if it's a driver issue, a scheduled task I missed, or something deeper. Anyone else run into this on Windows 10 and actually found a fix?