I would recommend using ChoiDujourNX if you wish to update to 5.1 so you can still downgrade to 4.1 if you wish to use the future exploit that doesn't involve a jig and USB cable. After that, I would recommend either using ReiNX or Atmosphere which can be found at reinx.guide or tomGER's SD files respectively. RajNX is not the most user-friendly as there are no instructions on how to customize it whatsoever.
OK thx a lot