Language learning is so subjective and personal, I love it!
As a linguist, do you feel that the process involved in studying languages (any language) is useful to studying others? For example, I learned Mandarin before German, but I found the formality and strictness of German spoken grammar really helped me to improve my reading and writing in Chinese. While being a native English speaker really helps me with spoken Mandarin because both are very flexible in comparison to German.
I don’t have much experience with Japanese beyond Kanji, but I know a lot of Japanologists in our department really struggle with Kanji. It also takes the Sinologists a lot longer to get up to the same reading level as those specialising in Japanese and Korean.
Are you C1 level in all three languages? That’s bloody impressive, I must say!