You missed the point I was trying to make when I asked you to solicit opinions from your team. You said that as a result of her complaining, the work you were getting was too easy and not very complex.

Sorry, I'll clarify. We were estimating the development of a UI. It was a well design, moderate/complex UI. We estimates its development, but she wasn't happy because she would still have to devlop a "moderate/complex UI"

So, she didn't keep her head down and found a way to spill this issue with my boss during the estimate's review, and he backed her up saying that "we have to work with the designers to make the UI accessible"

This was not an issue. the UI did NOT require any refinement to make it "easier to impelment", and instead, I found myself dealing with this stupid social situation just because "one of the devs ddn't want to risk developing a hard UI"

The problem you're describing appears to be more of a symptom of a wider malaise.

I agree. I hope my boss switches gears soon. He IS reluctant to say "X is the boss, listen to him/her now on issue Y"

His style of management is still the same one he had when the company had just 3 employees. I hoped my promotion was a step forward, tbh.

However, I could also be overreacting. My official promotion happened a few days ago, and maybe he's waiting before telling them about this change.

However, the idea of him not enforcing hierarchy is... infuriating.