Absolutely not. I would argue the defining characteristic of being evil is being absolutely convinced you are doing good, to the point of ignoring the protestations or feelings of others.
The defining characteristic of evil is privation of good. Plenty of evil actors are self-aware, they just don’t care because it benefits them not to.
Disagree. I actually think no evil person has the thought process of "this is bad, but I will personally benefit, therefore I will do it."
The thought process is always "This is for the greater good, for my country/family/race/self, and therefore it is justifiable, and therefore I will do it."
Nothing else can explain how such evil things happen, that we see actually happen. C.f. Hannah Arendt.
You think your average, low-level gang member, willing to murder a random person for personal status, thinks what they're doing is "for the greater good"? They do what they do because they value human life less than they value their own material benefit.
Most evil is banal and pedestrian. It is selfish, short-sighted, and destructive.