I have KDE neon and recently it was upgraded to the latest version, 5.23. The problem I have that System Monitor Indicator widgets no longer working, they are just empty, like this:
When I open settings for that widget and go to Sensors page, there are no sensors available
I have the same issue on at least 2 different installations. Strangely, I can't find any informaiton about it anywhere. Is there any fix available?
Check if you have ksystemstats installed by running it in Konsole.
ksystemstats
If it appears not found or not installed, try to install it.
sudo apt install ksystemstats
then try again running in konsole (you will see that it initializes)
ksystemstats
and finally open System Monitor.