1
It is normal for Windows to use 4GB - 5GB of RAM just for the operating system alone, Windows 11 is very resource hungry.
2
Workloadssessionhost is a process in Windows usually on Copilot+ PC's used for the Ai functionality.
Open the Settings App.
Go to Settings - Privacy & Security
Disable or reset the Recall and Click to Do settings to check if that reduces the resources used by workloadssessionhost process.
3
Browsers like Chrome, Edge... etc. are among the most resource hungry apps installed on your PC, try to minimize the amount of tabs you have open in your browser to lower its RAM usage.