I had never heard of Learn Korean in Korean but this seems really good indeed! I don’t know your level of German but if you’ve already reached an intermediate level, “Deutsch mit Marija” seems to be similar in teaching German by using German (That’s definitely too difficult for me currently though, so I can’t attest of the quality!)

I haven’t checked every channel either but I guess there should be something in this list on FluentU?

If only it wasn’t so hard to find what we liked!

Viel Glück!