Astarion and Minthara is the perfect partners in crime for a evil playthrough. I never felt the need to call them out. Maybe I did in my first goodish playthrough, I can't remember.
I can imagine Astarion being a bit annoying if you are strictly playing a good Tav, much as Karlach is a bit annoying on a evil one. As for gaslighting, never felt that.
Astarion is evil and that's why many players love his character. Zayir has some interesting psychoanalysis on why. I agree it is very important to separate fantasy from reality. It's a huge difference between enjoying horror and wanting it to be real.
I like horror in fanatsy, but the news? Nope, I can't watch it at all lately with all the horrors of war on.