The gap between textbook and real Japanese is not slang or speed. It is aizuchi: in Japan the listener is expected to speak every few seconds.
JapanesePod101 runs a twenty-five lesson casual series and Bunpro alone makes you type the casual form. The polite versus casual axis is the wrong picture.
A native speaker who produces pitch accent flawlessly and cannot consciously hear it tests the apps that teach it, and asks how much it really matters.
Most roundups of Japanese learning apps are written by companies that sell one. A native speaker in Tokyo judges them on the Japanese itself.