CreamCloud0
Hero
this is besides the point but that's not what the 'then let me be evil' trope is, TLMBE is where a good character who is perpetually accused of 'being evil' regardless of their actions suggesting otherwise stops trying to prove to people they are actually good and decided to become evil for real.is what TVTropes would call "Then Let Me Be Evil"--namely, the process where a character who thought they were doing good realizes they were actually really evil...and thus decides "well screw it, then I'll be evil!" Because that would be precisely the process of becoming unrepentant evil--knowing, intentional, embraced evil.
zootopia had a nice clean example with nick wilde the fox, an attempted boyscout turned conman: "If the world is only going to see a fox as shifty and untrustworthy, there's no point in trying to be anything else."