I used to do these challenges in codewars a lot but recently I've moved on to hackerrank and codeforces. The contests in codeforces are really intense and I like the pressure of timed events which you can't get in codewars.
Also another reason why I moved to codeforces was that in codewars you only need to complete the given function while in codeforces you need to write the whole program from taking inputs to returning the outputs which I think is better in the long run.