During the development of the Korean language learning system, we need your feedback!

Hello! I am currently developing a Korean language learning system. This system will start with YouTube and a simple Korean-based SRS mobile app, and in the long run, I aim to develop it into a more complete form. For example, I am considering structured lessons, more apps, or even website development. It's still in the early stages, so there are only a few videos, but before setting the direction, I would like to hear the opinions of those who are actually learning Korean. What was the most difficult part of learning Korean for you? Do you prefer a systematic course by stages, or do you prefer more free and exposure-based content? What do you think is often missing in Korean language learning content (YouTube, courses, etc.)? If you could design the ideal beginner experience, what would it look like? Are there any app features or website features that are still not well implemented for Korean language learners? I really want to hear about your experiences and opinions. It's okay if they are not related to the above questions. Thank you!