I read that dog and dragon don't work as noblemans in bazi.
If you study Shen Sha or Symbolic Stars in Bazi, that is correct. Out of the twelve Branches,
only Dog and Dragon (Xu and Chen) are not defined a Nobleman's Star for any Daymaster (DM)

Tianyi Guiren = Nobleman's Star
what does it mean if you have dog or dragon in your bazi?
what are the effects of this gate in your bazi?
what if its located in your year, month, day or hour pillar?
What does it mean? We don't know, because we need to analyze the whole chart. Is it
inauspicious if you have a lot of Chen and Xu? We don't know. At least what you can do is not worrying.
And I can give you an example of a very
noble chart with Dog and Dragon (Xu and Chen):
Al Pacino, Wu Daymaster:

He has been a very successful actor with so many awards and accolades throughout life. If you think that LP Chen or Xu will hit him, then that is not true, either. He was in LP Xu from 1992 till 2002, and in 1993 he won the most prestigious Academy Award for Best Actor.
If you look at his chart, as a Wu DM he does not have Wei or Chou as Tianyi Guiren in his chart. But he is still very noble in his field.
Note:
I used to study Shen Sha in great details. Since the day I studied Mangpai (Blindman), I was shown that very very few Shen Sha actually work, and I have myself seen so many charts for verification. That's the reason that I can quickly produce that chart as an example.