This guide will show you how to have CPU/Ram usage and temperature displayed in wingpanel. Open the terminal and copy/paste;
sudo apt install com.github.stsdc.monitor com.github.stsdc.monitor
Now click on the “Settings” (right top) of Monitor and enable Show an indicator. If you want it to start in the background enable that as well. You may want to add com.github.stsdc.monitor to Startup if you want it displayed automatically when starting the computer on (settings —> Applications —> Startup).
That’s it! Enjoy!!! ^_^
Tested on: elementary OS 5.1.7