Many moons ago I heard these lines:

  - "Just when you think you're the smartest, know that there's someone out there that's just as smart and probably ten times smarter!"
  - "There's no such thing as an expert"

They keep me humble :)

Loss of morale is what undermines the persistant efforts needed to make great things happen.

Having a healthy ego and doing objectively great things to feel good is not in itself 'toxicity' that must be 'killed'.

Freud would say the ego is the mature part of your mind that reconciles archaic demands from the undeveloped id with reality.

In pop culture ego is conflated with what Heinz Kohut or other modern psychoanalyst would call narcissistic disturbance and has to do with instability of the self-image. Even high functioning people teeter on the edge of feelings of grandiosity and worthlessness.

It is not a ‘big ego’ but an undeveloped ego.