I just installed latest Neon with plasma 5.20. I'd like to have taskbar 32-48px high and Panel icons in two rows - but they switch to two columns only at 56px height.
Is there a way to make those icons smaller (I see there is an option to make them "grow" with the panel in 5.20, but not to set the size...

Thanks

I changed your question: Tray is not the same as Panel. The Icon size of the System Tray can't be modified.

If you use the "Icons Only Taskbar", you can select the number of rows and for it to use that exact number of rows.