I managed to reach around the middle of the Void layer with Nix using a setup of Regen Sigil, Violetheart Pendant, and Ironhide Greaves. As long as we maintain shield stacks, we can safely ignore the Sporebound debuff and keep digging downward, just be sure to carefully balance the shield gain/loss vs stamina recovery. I swap out Violetheart for Verdant Radiance in Shimmera.
With this setup, it definitely feels doable now. Just be careful in the Void layer, since each dig effectively costs 2 stamina due to Wither, regardless of shield stacks.
