The thing about confirmation biases are that they are at the subconscious level and you likely wouldn't be able to detect them. It's possible that you have an impartial and immune to confirmation bias interview process, but it's also possible that you are indeed deciding (skewing) most of your interviews in the first several seconds.
> Hiring is literally the most important job a manager has in any fast growing company. It should be taken very seriously and systematically
I agree. Which is why, if it is found that hiring committees are more effective, and your company isn't using them, then are you taking them seriously? The same with bonuses and promotions. These should not be decided by a single person (manager).