> But mobile platforms, with their small touchscreens are completely different from desktop platforms with their large screens, keyboards and mice. So what do you do?
Which problem exactly? It works just fine. Just like there is no problem with well-designed websites that can work both on mobile and on desktop (like HN).
This is not an example from KDE, but you do convergence: https://videos.puri.sm/pureos/l5-convergence-purism.mp4