I have finished the first 2 maps on Curse VII and the rest on Curse VI. Difficult but doable.
Tips to Beat All Maps
Movement speed and Area get a lot stronger on the high Curses because you really want to stay as close to just off screen with the 4 Guardians as possible. Being further or closer leaves you open to too many dangerous attacks. Staying on top of destroying shrines as they spawn is important. Play with effects opacity at zero or one tick from zero.
The builds I use primarily focus on skills that hit very fast and can be used from a safe distance relatively early in a run. Take poison damage early at a pretty high priority so Debilitating Poison (the one that adds Doom to Poison hits) can drop. If it does, spam that attack speed, multi-attack and poison procs to the moon baby.
In my experience the best two heroes are the Elementalist (stack Lightning Storm and/or Tornado) and Death Knight (bladestorm/festering strike/perhaps a flurry). Ice Vortex spam works on either hero as well if the opportunity presents itself. Take a Bloodlust in either case and invest heavily in it.
I don’t know the rune names but my preference is the 5 cost one that lets you use the same ability multiple times, the 2 cost that is 5% damage bonus per debuff, improved multi-attack, and the free weapon skill on the Elementalist. Same for DK but the free weapon is kinda pointless as you’ll replace it. You might be better off going for a swing rune.