hCaptcha is actually the most effective, rather than keyCaptcha. Especially if put in the higher settings.
Looking at your system, you dont have all methods switched on at present. You should add some question and answer items. Ensuring you add questions which your potential members would answer easily, but would not be answered easily by a bot. For example, if you put something like "What is 2+2" its likely a bot will breeze through that. Add a few of these.