The better Nietzscheans here can answer your questions better. Until they do:

One thing I can say confidentally: Nietzsche wasn't looking to supplant one (Apollonian) with the other Dionysian). He thought both were necessary.

He also, definitely, didn't think we should create new values from scratch. He didn't want us to repeat old values, sure, but the process of creating new values isn't sketching on a blank canvas.

From here I defer to the resident Nietzscheans.

My question is this:

If I have a good basic understanding of Nietzsche; does this mean that Nietzsche saw everything as bleak, meaningless and harsh? Another question is: Would his overman would end up being an iconoclastic narcissistic brute who carves out his own meaning for himself on his own terms? — Agathob

The better Nietzscheans here can answer your questions better. Until they do:

One thing I can say confidentally: Nietzsche wasn't looking to supplant one (Apollonian) with the other Dionysian). He thought both were necessary.

He also, definitely, didn't think we should create new values from scratch. He didn't want us to repeat old values, sure, but the process of creating new values isn't sketching on a blank canvas. — csalisbury

I fail to see how this answer answers the two questions asked.

I believe I have a fair idea that he believed all Apollonian moral systems were inherently flawed and needed to be replaced with a Dionysian based one that he felt was more life affirming in a harsh and meaningless world. — Agathob

Nietzsche admired the Greeks for the harmony between the Apollonian and the Dionysian. This is logical because the Dionysian means destruction. It is necessary but by dose.

does this mean that Nietzsche saw everything as bleak, meaningless and harsh? — Agathob

Everything is not bleak and harsh. Life is something bright and exciting. Nietzsche was elitist. He thought only a minority of select spirits were capable of living life to the fullest. The rest of us are sickly resentful people who cling to anti-vital forces.

Would his overman would end up being an iconoclastic narcissistic brute who carves out his own meaning for himself on his own terms? — Agathob

It is difficult to fully understand the theory of the Overman. On this point Nietzsche expressed himself metaphorically. But the Overman is not a brute. He must be understood as a spirit superior in sensitivity and vital power. Narcissistic is not the exact word. Individualistic in the extreme is. Nor does he disdain violence, but he does not exercise it to dominate anyone but to grow. Some historical models that Nietzsche considered superior were the tragic stereotype of "great men": Cesar Borgia, Napoleon and the Aryan warriors (not to be confused with modern Germans). Actually, they were more literary than historical.

Great response, ! I learned from you more about the nature of the Ubermensch than from anyone else before, including Nietzsche himself. I ain't joking and I am truly grateful.

Metaphorical expressions always present some difficulty via some unavoidable ambiguity. This is what saved the Christian faith and churches. The Bible was converted from factual to metaphorical, thus saved because it became a book up for interpretation and arguable ambiguity, instead of the original intention of getting written, which was to recount straight facts.

There are still some churches and Christian sects which consider the Bible to be believed on face value of its claims, such as by the Baptists; this explains one of the highest rates of apostatism among all Christian churches (up to 20% of followers per lifetime, by some estimates.)

I find Nietzsche views to be somewhat flawed and based more on stereotypical views of human nature or perhaps some overly romanticized views of "the past", ancient Greece, and so forth. (Such as the difference in theory and practice of having "status" or whatnot within the actual context of an organization and its values, rather than a simple romanticized or 'idolized' picture of a 'famous' historical figure "in a vaccum" or artistic portrayal, devoid of any of the actual context or understandings thereof which would make said 'status' meaningful, or able to exist at all to begin with).

I'm also very skeptical whether or not Nietzsche himself would fit the definition of "overman", given that he was primarily just known for writing and popularizing his ideas, rather than any of the stereotypical accomplishments he made.

Much as I see no reason, why Jesus would not, ironically, be considered more of an 'overman' than Nietzsche himself, ih terms of his lasting accomplishments and legacy, regardless of whether or not one believes he is the "son of God", or anything else.

Likewise, a 'meaningless' view of the world, to me, wouldn't be particularly conductive to the note of being an "overman", or any feeling of drive or obligation to be so; beyond uncontrolled, meaningless impulses which would just as well be subordinated rather than gratified - for many, if not most, if life is "meaningless", it would be in one's more immediate interest to do as little to nothing as possible.

I'm also tempted to argue that most of the so-called "red pill" stuff which has a cult following on social media, is kind of a dumbed down, adolescent, poor man's version of Nietzschean existentialism, rather than anything particularly 'original' or not obvious and commonsensical enough to merit taking a "red pill" to begin with, that hasn't existed or been said in some variety or another by a myriad of different authors, or predicated on simplistic, childish stereotypes and conflations that have little to no bearing on reality to begin with, outside perhaps of some childish Jungian archetype or symbolism of sorts, usually having nothing in reality to do with "religion" or anything else that anyone above and beyond a 6th grade reading level would have been though to be readily aware of, in theory and in practice.

I think that Nietzsche's filosophy is nicely expounded in the film "Dark City", one can watch there an ubermensch in action.

https://www.imdb.com/title/tt0118929/

Metaphorical expressions always present some difficulty via some unavoidable ambiguity. This is what saved the Christian faith and churches. — god must be atheist

This is true. But metaphor is the core of literary expression and Nietzsche was as much a poet as a philosopher. This makes reading him exciting, sometimes with admiration and sometimes with horror. The official history says that Nietzsche fell into madness in 1889. I think that madness was haunting him long before that. But you mustn't disdain crazy people. Sometimes they're the ones who tell the truth that we "sane" people don't want to see.

Yes, madmen and madwomen (and madchildren, to a lesser degree) have a different slant on reality. The insight usually wanes with a major nervous breakdown, though, the person likely loses even his previously well-used survival skills. What I'd suggest is that some madwo/men (not all, in fact, the same proportion as in the normal population) are intelligent, and before their breakdown they produce their life work, if they do. After the breakdown, nothing comes of them. Nicolai Tesla, Gogol, and it looks like Nietzsche are prime examples. Hamlet went questionably mad too, but he was a character, as we all know, not a writer albeit very much a thinker.

And metaphors are like inverted amphoras of meth: the taste and the richness are on the outside, but the artful design is on the inside.