Hello. Using Kubuntu Bionic with latest KDE packages. (khotkeys is at 5.12.6. Tell me if I need to report any other versions.) I'm using the Workman layout for my Latin script text entry as I find it is kinder on my hands and fingers than QWERTY. It is my first layout under System Settings > Input Devices > Keyboard > Layouts. I find that I am able to use the Meta (aka Gui aka Win) key only in combination with the following 10 letters to launch apps: QDW ASHGY ZX and not with the following 16 letters: RBJFUP TNEOI MCVKL If I am using QWERTY I am able to use all 26 letters. All other operations using combinations of Ctrl or Alt with these keys are working fine.
As announced in https://pointieststick.com/2023/07/26/what-we-plan-to-remove-in-plasma-6/ and https://community.kde.org/Plasma/Plasma_6#Removals, I'm afraid KHotKeys has reached end-of-life in Plasma 6. Accordingly, all bug reports and feature requests for it must be closed now. Most of what KHotKeys could do can already be done with the newer KGlobalAccel system in Plasma 6. A few features such as mouse gestures and triggering conditions based on changes to window states are not yet implemented in the new system. These will be added in the future if and when resources materialize for them, and/or when a kind soul submits patches to implement them! :) Meanwhile, the 3rd-party "Mouse Actions" app (https://github.com/jersou/mouse-actions) may be usable for implementing your own mouse gestures again. Thanks for your understanding, everyone.