Dell Desktop W10 Home: Internet Preventing Sleep Mode

[supraomutf]

My Dell desktop running Windows 10 Home is set to idle overnight, but it only successfully enters sleep mode when the internet service is interrupted (e.g., by turning off Ethernet or the router). When the internet is active, the machine attempts to sleep but wakes up shortly after, and this cycle continues throughout the night.

Is there a setting I can adjust to prevent the internet service from waking the computer?