I had the same problem Task Coach not being in the packages on Kubuntu 20.04 and not being able install it anyway. So I created an AppImage. Try it out if it works ok for you. https://github.com/fluks/taskcoach-appimage/releases/download/v0.1.0/taskcoach-appimage-0.1.0-x86_64.AppImage The script to build is also there with instructions how to build it. Feel free to make the script better.
I had the same problem Task Coach not being in the packages on Kubuntu 20.04 and not being able install it anyway. So I created an AppImage. Try it out if it works ok for you. https://github.com/fluks/taskcoach-appimage/releases/download/v0.1.0/taskcoach-appimage-0.1.0-x86_64.AppImage The script to build is also there with instructions how to build it. Feel free to make the script better.