[scrawl]

i love k. it's a much smaller and regular language than APL and some of its derivatives. you can look at John Earnest's oK. it's fantastically documented and a great learning resource.

i would also recommend BQN. it has an active community and it's designer Marshall Lochbaum explicitly tried to address some of the warts in APL and j. he's done a great job.

learning any of the array languages will be a tremendous learning experience if you haven't approached the paradigm before