yo this app is actually good huh
essentially learning a second language after the age of 6 or so to a native level is very hard if not impossible, almost everyone has a foreign accent or at least some other issues. He speaks the language perfectly, even his reading level is better than most japanese people which is impressive
tldr there is a "better method" to learn language if you're thinking about pronunciation and time is not a problem.
https://www.youtube.com/watch?v=M0Ncawy2LJc
if i were you, i would lose sleep over this perfect app. the bird keeps me awake at night to make sure i pass my classes!!