(1) The type of speech you describe could be called bluster and a person who blusters is called a blusterer
bluster 1. Talk in a loud, aggressive, or indignant way with little effect.
(...) at least this bullying blusterer of a politician was prepared to take action (...)
[Pl. click on the 'example' button in the above linked page to read the full sentence and more instances of its use]
(2) An idiomatic expression that suits your description would be cock of the walk
cock of the walk [noun] : the leader in a group, especially one with a conceited, domineering manner.
Definition of 'cock of the walk' at Collins dictionary online
(3) You should consider adjectives as well, because the vast majority of the appropriate choices for your question are descriptive words rather than nouns, and one descriptor that fits your case well is overbearing.
1a: tending to overwhelm : overpowering
2 : harshly and haughtily arrogant
the mayor's overbearing manner of dealing with employees
Definition of overbearing at Merriam-Webster online
Moreover simply googling 'overbearing' opens up a large number and variety of terms that are close in meaning:
(...) overbearing : unpleasantly overpowering.
"an overbearing, ill-tempered brute"
synonyms: domineering, dominating, autocratic, tyrannical, despotic, heavy-handed, oppressive, high-handed, bullying, high and mighty, lordly, lording it, officious, masterful, dictatorial, bossy, imperious, pontifical, pompous, peremptory, arrogant, cocksure, proud, overproud, overweening, presumptuous, opinionated, dogmatic; More
informal: pushy, throwing one's weight about, cocky
See Definition and synonyms of overbearing by Google
(4) In terms of a specific label, you could sarcastically call an overbearing person a despot / tyrant / dictator, where the tyranny lies in dismissing the ideas and opinions of others. I have read of such types described as a great dictator or a little dictator.
My mother-in-law is such a dictator.
Back to your desks, look right industrious and don't talk back -- the great dictator is just stepping out of his cabin!
It can be fairly trying to work with this little dictator.
In India I have heard such a person sarcastically called a Hitler (as in 'be cautious while working with so-and-so; he is a Hitler!') but I understand any reference to Hitler would be highly controversial in Europe and maybe also in the USA. Other possible labels are little king, little prince, and little lord which can be likewise deployed sarcastically to refer to the person's overbearing behavior.
He ran the office like a little king and earned the ire of his staff members.
"I been tryin' to do this job the best I can, but I got my work cut out; and the little prince with his bossy ways ain't makin' it any easier, for sure!"
"The little lord has no sense, but brooks no argument -- just talking to him gives me a headache -- this business is going to sink within the year."
You might get some more ideas by reading the comments and answers to this closely related question asked earlier at this same website:
What is a word for someone who likes bossing people around?