I think the comment to use one of successor languages is most pragmatic. I learned with stickers on keyboard, you don't want to do that, and a dedicated keyboard sounds kind of silly (this from former pro IBM APL2 programmer, it was my 2nd language).

However, I don't really like the digraphs/glyphs/whatever that J uses that much, i think there's a mode where there's short forms like "rot" for rotate function, "ind" for index etc, look for those.