Good choice. Before you start, did you already back up your important files to OneDrive or an external drive, just to stay safe?
The Media Creation Tool will let you run a repair install of Windows 10 while keeping your files and apps. Download the tool from the official Microsoft page, run the setup, pick Upgrade this PC now, then select Keep personal files and apps. The process replaces system files and often fixes performance issues without removing your games or programs.
Since you prefer to stay on Windows 10, this is the supported path to refresh your system without moving to Windows 11.