It's hard to give an absolute answer without the rest of your team, but just going off of opposing Lando destroying the rest of your team, I would say go for either the special set or a mixed one. It's always a bit of a shame to miss out on STAB EQs from a 145 attack stat, and even with no special investment, HP Ice OHKOs non-defensive Landos after Rocks:
0 SpA Life Orb Landorus-Therian Hidden Power Ice vs. 0 HP / 0 SpD Landorus-Therian: 286-338 (89.6 - 105.9%) -- guaranteed OHKO after Stealth Rock
Although you'll need 124 EVs if you don't want to rely on Rocks:
124 SpA Life Orb Landorus-Therian Hidden Power Ice vs. 0 HP / 0 SpD Landorus-Therian: 322-380 (100.9 - 119.1%) -- guaranteed OHKO
Landorus-Therian (M) @ Life Orb
Ability: Intimidate
EVs: 252 Atk / 4 SpA / 252 Spe or 132 Atk / 124 SpA / 252 Spe
Naive Nature
- Earthquake
- Hidden Power [Ice]
- U-turn / Stone Edge
- Stealth Rock