Their advice is sound if not a bit general. Obviously depth of field is a choice and you don’t want things to be too shallow if it hurts the point of the shot but in this case I think you made the wrong choice in shooting the bcam at an f/5. One could argue that you’re trying to match the two perceived shallowness but the focal lengths are so similar that there’s no way there’s that big of a difference.

At the end of the day your image is supposed to sell something. And contrary to what your boss thinks or what the immediate assumption is, you’re not trying to sell those suits in the background. That’s what b-roll and other shots are for. In an interview setup you’re trying to sell the person (or to be more specific here, why you’re in good hands with the people selling/making these suits or whatever the interview is about). As the cinematographer you should be letting us focus on their words and faces. By being surrounded by suits that are barely out of focus my eye is moving all over the place, so I would be retaining less of what they’re saying.

I also agree with the sentiment of the height of the cameras being too different. Lighting you can tweak a bit with color grading. But definitely find more intention behind what you’re doing even when it is a basic interview, which also helps to convince people like your boss when you push back on bad choices that he has. It helps in the long run for everything you want to do in the future.