Some evil characters are the most loved in fiction like Joker, Dexter, Pulp Fiction, Blacklist, etc. I mean, a lot of times people root for the villain!
...Edwin, Korgan, Viconia...
I don't have much of an opinion on the companions in BG3 yet (though I'm probably not going to like most of them), but you can by all means make a character that is both evil and likeable.
