> There is more to life: I am an engineer; I like solving problems. I embrace fairness and open intellectual exchange. This matters to me a whole lot more than getting promoted. Plus, "giving in" does not preserve peace—it simply appeases bullies and makes the workplace toxic.
OK, yes, but, how about: "I am still not convinced, BUT I realize neither of us are going to convince the other one right now, and I've been wrong before, let's try it your way this time."
This is not appeasing bullies and making the workplace toxic. Sometimes insisting on arguing everything out forever every time you think you are right is what is in fact accidentally being a bully and making the workplace toxic. (And I have definitely been that person; I am not to my knowledge autistic, although some people have wondered sometimes).
I think people can mean either one by "giving in", I am wondering whether the OP, in rejecting "pretending I agree when I don't" is accidentally being the person who "always insists on getting their way every time".