New managers face expectations no one talks about. Guess what the company means by "a good manager."
Be responsible for everything the team does. Stay strong and senior, but take the blame when something goes wrong. The rules are hidden, the mistakes are not.
Performance reviews and one-on-ones are the only formal practices in place.
Everything else: goals, feedback, delegation, control - is left to each manager's interpretation. There's no shared management practice the company has defined and reinforced.
The new manager is expected to track motivation, KPIs, conflicts, and burnout in their team; meanwhile, no one runs one-on-ones with them, asks how they are doing, or watches for their burnout.
The pressure comes from above and below at the same time, and the manager carries it alone.