Personally, I would go for Eviolite Galarian Corsola. With Eviolite boosted Defenses, it's arguably better than Cursola, plus Shiinotic is worse than both Cursola and Corsola and Polteageist very rarely runs Strength Sap.
Corsola-Galar @ Eviolite
Ability: Cursed Body
EVs: 252 HP / 4 Def / 252 SpD
Calm Nature
IVs: 0 Atk
- Strength Sap
- Night Shade
- Will-O-Wisp
- Stealth Rock
Pretty simple. Eviolite boosts its Defenses. Cursed Body can disable moves that may be dangerous (also causing Choice item Pokemon to Struggle). 252 HP is for bulk in both Defense and Special Defense at the same time. Maxing out Special Defense with Calm and 252 EVs is pretty important, since Will-O-Wisp and Strength Sap already cripple physical attackers. Strength Sap is the point of this answer sooo.... yeah. Night Shade is so you aren't complete Taunt bait. Will-O-Wisp cuts the Attack of the target, which is nice. Stealth Rock is for entry hazards.
Hope this helps! :)