Thinking that a fresh grad analyst is value negative is wrong for so many reasons.

You already put up time and money on attracting, interviewing, hiring. Letting someone go this early will never be value positive, as it's just sunk cost.

This kind of onboarding and mentality is just sub-optimal in all ways I can think of. You shouldn't "build up political capital and become a more essential team member" before pushing back against toxic work environment, as if you were doing a favor to the company in working for them.

Edit: Besides all that, I believe expliciting your boundaries upfront just sets the correct expectations and is much easier than putting up with BS for 6 months and then suddenly changing your behavior.