If you enable block subsequent, now it only blocks the events processed by the action map. For example, if the menu uses only some inputs, I can still control the game beneath. I think it would be more logical, if an action map would block all events.
If you use ActionMaps for all input, then it should work. If you have things in your game that get input by querying the old Input APIs (though the Input class) then that won’t be blocked. We can’t change behaviour of how the old Input APIs work.
I use ActionMaps for all input, I know that you can’t change how the old API works. Maybe I’m mistaken, but if I remember well, I had to tweak with the code so the blocking ActionMap blocks all events, even if it is not consumed by it. I will redownload the new input system and check if it is not the case.