Created attachment 131348 [details]
Screenshot.

SUMMARY

If the icons only task manager is used it may happen that depending on the number of entries, the scaling and the panel height, the icons become unusable small. Please see the screenshot.

One can also observe that the virtual desktop switcher scales fine with an increasing panel height, i.e. taking more with a bigger panel, while, the taskbar icons don't like to be scaled only in y-direction and eventually become so narrow that the even icons won't be displayed any longer.

Maybe a minimal and sane icon size can defined and if the space becomes too small, a drop down panel like for the systemtray could be used to display icons which no longer fit? Probably you know a better solution?

At least that would keep it usable -- even if the vertical / horizontal scaling of the icons are far off being ~ 1.

SOFTWARE/OS VERSIONS
Operating System: Manjaro Linux
KDE Plasma Version: 5.19.4
KDE Frameworks Version: 5.74.0
Qt Version: 5.15.0

ADDITIONAL INFORMATION
Scaling: 2.0