1. You should have reported him to the FSDO after consulting with your CFI.
Too many DPE’s get away with too much BS.
2. I’ve had initial CFI applicants fail twice, first time legitimate and second time they just had a brain freeze moment and got themselves all wrapped around the axle.
That’s human factors.
3. Since you didn’t report the DPE you’ll have to come up with ( for a recruiter) an acceptable explanation as to why you failed 3x
In my opinion it’s perfectly acceptable if one of those is “human factors” as in you just became your own worst enemy.
4. You’re on the right track. Be the best you can be in everything you do.