The InitializationSystemGroup is not part of the Update phase of the player loop. If you have the default settings for the Update Mode in your input settings, then WasPressedThisFrame() will never trigger to a system in the InitializationSystemGroup.

You can either move your input reading into the Update phase (probably within the SimulationSystemGroup), or change your input settings update method. The option to process events manually has some caveats that you should be aware of if you take this route.

To me, putting the input reading at the start of the SimulationSystemGroup makes the most sense and should capture all input before it is needed.