[giantg2]

I'm pretty sure I am. I've even had a manager tell me in a 1-on-1 "not everyone has the potential to be more than a mid level". Here I am 10 years into my career and still a midlevel.

[Zetice]

That person is awful at their job, ignore them.

[giantg2]

Even if I ignore them, it's hard to ignore the facts.

[Zetice]

Like the fact that you’re incredibly insistent that a random stranger believes you’re dumb?

[giantg2]

More like all those "random strangers" that have been my managers.

[Zetice]

This screams “low self esteem”, you really ought to see a professional about it.

[solarmist]

With what you've said, it makes sense to feel that way. I would encourage finding ways to think about it/express it, one that doesn't make it a character flaw.

Can you phrase it in a less absolute/intrinsic way, though? "I am a dumb dumb" isn't a solvable problem.

I encourage you not to personalize this (Using "I am"). You may not be a mediocre software engineer, but that does not equal YOU being a dumb dumb.

That's a false equivalence. I'm sure there are areas where you are not a dumb dumb.