1) 3s are, unlike 7s, not narcissistic without merit because they have esteem based on success - so they are pretty much self critical and self aware
2) Threes arent born to be competitive, unaware shallow beings - they are born to become the most authentic of all types (in enneagram gift is what makes most problems at the same time), so healthy 3 would be "I dont take this fake BS anymore! enough! I want to be authentic and havd my own goals and values. " and can very easily spot BS/masks in other people bc they have seen through themselves and their potential blind spots
Ex., i am 1000% i am a 3 and i kind of even despise fake tendencies in me to a point of doing everythinng to become authentic. I think i am more self critical than most non-3s in this aspect because i am awakened and ive seen through my own masks.
It goes with being NF and not tolerating inauthentic life
ESTJ 3 would tolerate it for much longer if not forever
In my own case there is also asoect that i had many huge personal tragedies that urged md in the last few yrs to search for myself and not take my own BS.
And last and most important ; comment on general direction of this thread : Enneagram is NOT DESCRIPTIVE system!!!!!!