Thrawn

i recommend you look into why your persona became a villain. a simple "wants to kill everyone and dominate the world!" won't make for a good storyline, but rather look into why they believe that they are in the right, and what caused their perception to warp in such a way that they are now considered the villains of a certain story you are creating. whether they have been indoctrinated into a cult from a young age, or severely hurt by a certain community to the point of snapping, etc.

not at all

my advice is that, if you wanna play a villain that will actually impact people's character and leave a lasting impression, take the time to really ground your character the world, consider why they act the way they are, and really get a feel for how they influence those around them. imo, some of the best villains are villains with motivation and justification, rather than "evil for the sake of evil," because having a story to work with is what builds narratives and storylines. the more substance you allow a villain to have, the more engaging your interactions will be and the more avenues of RP you'll have

Don't listen to unwillingly everyone tries too hard to be morally gray be comically evil. Kick puppies and mock orphans with tuberculosis.