spend all points on your root and one on comprehension, get the manual to level 3 as soon as possible, max your sanity and do enought missions to have always 3 points, after you maxed your sanity just put 30/50 days to mantain it and try not doing quests that require sanity, spend all the time you have remaining on cultivating and save every so that when the waterfall event happens you can load back and try it again till you don't succed in gaining the bonus
P.S breaktrought as soon as possible, you can load the previos save to try till you don't succed