"Enable Mouse Keys" option in Accessibility not working

I am trying to control the trackpad of my macbook via keyboard but the "Enable Mouse Keys" option in Accessibility does not enable the mouse control which should be the 789UIOJKL keys. What am I doing wrong? OS: Big Sur Machine: Macbook Air M1 I have Alfred, Keyboard Maestro and Karabiner Elements installed but as far as I know the relevant keys should not be affected by any macros. Any way to debug this?