I would say Hela. While Wanda's power is immense, possibly on the level of an infinity stone or more with the Darkhold, none of that enhances her physical body- that we know of.
As such, while Hela might be able to survive Wanda's first attack, there's no way Wanda survives a single strike by Hela, which instantly killed Asgardians. Hela was fast enough to take out an army of Asgardian soldiers killing many of them with salvos of death blades.
If Wanda gets in the first shot she's got the power to alter reality and destroy Hela, but I'm not so sure she'd get that first shot.
I'll say Hela still takes this 6/10 times.