I use vertical taskbar. The buttons for opened programs should be personalized with: icon size, text size, multi lines text, max/min height.
Even with my taskbar had
100px I can read just a few letter, about 4 - 5 max.
hi, welcome.
vertical task bar havers are at a disadvantage in plasma as a lot of the widgets seem biased toward being placed into a horizontal panel (looking at you DigitalcClock.qml)
so short of some .qml hack, the only way to get what you are after is submit a “wishlist” item to bugs.kde.org or look for a 3rd party widget that does what you want.
i assume you would want the option to put the text under the icon, instead of next to it