Edwin

Everyone seems to forget about the clone training trick Naruto did to learn rasengan. He has had a clone in the hokage archives learning every jutsu every technique everything about shadow clones jutsu and sage modes. There is very clear evidence that he's been learning how to cycle chakra and boost it using clones to give himself a huge sage mode boost with nature chakra but in a infinite loop. Wether they continue ok with this or not remains to be seen