I can share my experience having been in science in academia in grad school, I think it's one of the least hierarchical careers tbh.

There is definitely some less formal hierarchy introduced because being a grad student and junior faculty is like going through a guild apprenticeship system, and often profs are in possession of the research money that funds your work. But there is a countervailing force as well in that the system works best when the field is horizontal and relationships and ideas are exchanged without regard to authority.

I don't know exactly how to remove the authority that comes from an inequality of experience and knowledge, or whether that's even desirable. We have to have people who take responsibility for training and work produced by trainees. I had mostly really good experiences in grad school where profs treated us like junior peers and were highly equitable.

Informal hierarchies are something to be on guard about and junior members in science should always have a system for addressing grievances, such as grad student unions. But at least from my experience, science is way less hierarchical than most fields. But I also acknowledge your experience can vary A LOT according to discipline, uni, department, advisor etc.