Learning to say no when it's not in your interests isn't adversarial, as an old boss put it pithily "If you don't respect your time no one else will".
I was hired to write software, we pay a third party for desktop IT, if I then start doing IT technician tasks I'd be the most overpaid IT technician in the country and we'd still be paying for support.
I was hired to write software, we pay a third party for desktop IT, if I then start doing IT technician tasks I'd be the most overpaid IT technician in the country and we'd still be paying for support.