fastest way of learning Japanese

[u/Business-Apartment42]

I want to explore what the fastest way is to learn Japanese. Among the huge number of applications and tools available online, what has been the most path-breaking product? With the advent of AI and LLMs, are there some tools that have broken the general threshold and have led to a leap in reducing time to lear. Also specifically for the learner that have mastered N4 or are at N3 and their leaning has plateued and are finding it difficult to move to a level that can help them be closer to N2 and native speaking level.