Ok, so there are four calcs that you would want to be aware of. (Pun intended).
+2 252+ Atk Incineroar Darkest Lariat vs. 252 HP / 252+ Def Unaware Quagsire: 112-133 (28.4 - 33.7%) -- 0.7% chance to 3HKO
So this thing has unaware, and it ignores the boosts. Let's say it gets turboblaze, just because I like the idea of a blazing quag boi. Anyways:
+2 252+ Atk Incineroar Darkest Lariat vs. 252 HP / 252+ Def Quagsire: 223-264 (56.5 - 67%) -- guaranteed 2HKO
See, so unaware does ignore the boosts. Now here's the thing. In the Unaware calc, I used defense investment and no defense investment in both calcs. Both gave the same result. So, therefore, Darkest lariat does ignore the defense boost, and unaware ignores the attack.
Hope this helps :)