Hello, I think a feature where you can sort your extra study by only kanji would be very useful (in extension you could also have this for radicals and vocab, although I doubt it would be as useful).
Today I wanted to practice the kanji that I was unsure about using extra study but I get a ton of vocab in there. I didn’t want to practice vocab at that time, because I was wanted to study the kanji required for me to level up. I think this feature would be a small but super nice quality of life change!