I recently started playing 1. e4. Since black has a big choice of replies, I would like to learn one opening at a time. If black plays something I haven't learned yet, I would like to resort to a King's Indian setup (pawns on d3, e4, g3, bishop on g2 and knight on f3) which I am familiar with and enjoy playing.
Obviously this backup plan does not work with all of black's replies (e.g. not with the Scandinavian 1. e4 d5). With most others it should be ok-ish, but perhaps there are also slight differences.
My question is: Against which openings is the KIA setup not all that great? Or alternatively, which openings should I learn first so that I don't have to resort to the KIA backup plan?