The default system monitor application that comes with KDE can do this. You will need to click the "edit page" button in the top right, and create a custom layout that shows all the sensors you want. Here is mine:

You can display the data using pie charts, text, line charts, etc.

Once you create your layout, you can even turn it into a widget that you can have on your desktop or drop into your taskbar.

btop in the terminal is awesome. It'll give continuously updated temps for each core as well as the temp at the outlet. Plus, it's pretty.

Every GUI tool just uses the data from lm_sensors, so you'll need to install that and have it identify the installed hardware sensors in your computer. After that, you can choose from a variety of GUI front ends; here is the Arch Wiki page with a list of common and popular GUI tools for this purpose.

I don't use KDE, but you could try https://gitlab.com/agurenko/plasma-applet-thermal-monitor

Psensor. It's gui only. I don't care for the graph so I just resize the window until I only see the numbers.

I just use btop, and even though they recently added GPU diagnostics, there's also nvtop.

For GUI tools, there's cpu-x and for Nvidia GPUs, there's gwe, but I honestly barely use them in preference of btop and nvtop.

For spot checks I just run sensors or watch sensors.
sar -m TEMP | grep amdgpu when I want to see history (needs the sysstat cronjob configured to collect sensors data).

Check out CoreCtrl: https://gitlab.com/corectrl/corectrl

For amd gpus you may want to take a look at amdgpu_top

Coolercontrol

Have you tried creating a custom page with the plasma system monitor?

plasma-systemmonitor

You can create a new page to monitor all your temps, then add rows for each sensor you want to monitor, select the chart type or text and then select the sensor itself.

I'm sure there are plenty of guides on how to set it up to get what you want.

Hwmonitor