up lvl hero

hi all. ! help me up my 6 star hero level fast.
should i up 3 star hero to lvl 50 and feed or not! because 3 star hero lvl 50 give 93k exp and chance xxx. i . i dont remember need how many ap potion. about 90 times auto play or more.. . should i do this. or lvl all my team. dont change any things. 1 time auto play = 7100 hero exp ( 5 hero ).1450/1hero.....
question: should i up hero 3* to lvl 50 and feed. or up 30 and feed. thanks for help ,,

i fed a few lv30s and a lv85 3* to my Ophy when i got her. but i didnt get a bonus shes at lv 77 right now. honestly the best way to level is wait for double EXP and spam dungeons lol.

At some point, even level 10 King Chests will provide only a smidgen of XP, and max tier/ max level 3* become more helpful to use to get those levels, plus you will complete albums leveling/evolving those 3* heroes, gaining passive stats and some rewards in the process.

~Thanks go to Lucky( on Jamel) for the max lvl/tier suggestion.