I've been facing a strange issue on my Windows 11 PC. After using it for 3–5 hours, the entire system starts feeling sluggish. Opening File Explorer takes several seconds, right-click menus lag, and switching between applications isn't as smooth as it is after a fresh restart.

The confusing part is that Task Manager shows:

CPU usage below 20%
RAM usage around 50%
Disk usage below 10%
SSD health is reported as good

I've already tried:

Updating Windows and all drivers

• Running sfc /scannow and DISM repair commands
• Disabling unnecessary startup apps
• Checking for malware
• Updating BIOS

A restart fixes the issue temporarily, but it always comes back after a few hours.

Has anyone experienced something similar? What could cause Windows to slow down even when system resource usage looks normal, and what advanced troubleshooting steps would you recommend?