ZMeter is a portable app for displaying your system's network, CPU, and disk details from a sizable desktop widget.
It provides you with up-to-date network usage, CPU usage with uptime, and whether there's a reboot pending, RAM usage as a percentage, and Disk usage, all in an auto-scaling graph. The interface can be set to be always on top and light or dark mode available via a right-click on the interface. ZMeter doesn't include any other configurations or settings and cannot be minimized to the tray, either it is displayed or off.
If you are looking for a system info app with a minimal footprint to keep you informed about specific information about your system ZMeter will fit the bill quite nicely.