Word on the street is vskill, j.mk, c.mk, legs repeat. Vskill, j.mk, s.mp, c.mk, legs works too, and so does vskill, j.hp, c.hp, sbk. On knockdown the cpu doesn’t block cross ups so df.hk, c.mk, sbk repeat til dead.
From my personal experience there are times where the cpu will switch up and give you a fight so be prepared. Also you get to start the current level over after an online battle so keep fight request on jic you start getting your ass beat. Set fight request to ask so the game won’t interrupt you if you happen to be winning.
Against sim sometimes your vskill will get beat by his arcing fireball so if you see him launch one dash into ex legs for the knockdown.
Standing hk owns gief for free, except the gief on lvl 45. He spd’s that shit on reaction so just fight and zone him as best as you can.
It seems like no matter what you’re going to have to get at least a little lucky to finish hard and hell survival with chun so get comfortable and prepare to break a stick/controller or two in the process. Fuck capcom for making unlocking colors such a chore in SFV. Hope this helps, good luck fellow chuns.