My self esteem has also been heavily based on believing that I'm really smart, but I never had a problem admitting I didn't know something. "Smart" to me means my ability to learn, problem solve, and make connections.
One of the most significant factors in my success to date has been my almost eager willingness to admit my lack of knowledge, and to ask others to share their knowledge.
How else are you going to learn new things?
Even the very word discussion comes from late Middle English (in the sense ‘dispel, disperse’, also ‘examine by argument’): from Latin discuss- ‘dashed to pieces’, later ‘investigated’, from the verb discutere, from dis- ‘apart’ + quatere ‘shake’.
We generally don't do a very good job of talking about things in way that brings those things, or us each other, closer together.
Very often, English-language experts can appear to defeat subject-matter experts in debates. When this happens it's usually because of footwork on the "language layer."
I remember the good old days, before the internet, when people would always admit their ignorance in real life and the Dunning–Kruger effect didn't exist.