Okay, so you have posted an excellent reply. It is clear that you have at least given the matter a cursory amount of thought.
I object to the materialist story on many levels that seem so clear and obvious to me that it is sometimes difficult for me to appreciate that people who buy the story are operating in good faith.
First, there is the fact that the story of Darwinian evolution driven by Random Mutation combined with Natural Selection has a simplicity to it that a lot of people appear to mistake for elegance and explanatory power. It makes sense of the beaks of finches on the Galapagos Islands, and we can extrapolate the process across a billion years, and so we assume that we can explain all life on Earth.
In fact, this is a case of explanatory powerlessness masquerading as simplicity and elegance. Merely conducting a naive extrapolation in one's head is not the same thing as "doing science". This whole subject requires a deep dive into philosophy of science because so many people are simply unable to define what science is or have a cartoonish definition to the extent that they try to explain what science is. It is notable that Darwinian Evolution is not easily accessible to experimentation and test tubes and randomized control trials, and whatever other catch-phrases people associate with "doing science" and yet people seem to think that it belongs in the category of "science" as opposed to "metaphysics".
To the degree that the theory has produced testable predictions, the most notable have to do with the fossil record, which basically just disconfirms the theory of Evolution at every turn. They fossil record demonstrates stasis along with the sudden appearance disappearance of various forms. It also contains periodic explosions of entire body plans seemingly out of nowhere. Not only is there "a missing link" in the fossil record, but "missing links" is characteristic of the fossil record across the board. It is the most notable thing about the fossil record.
At this point I am going to make an appeal to authority: the authority I appeal to is Stephen Meyer of the Discovery Institute. I highly recommend his discussion with Joe Rogan that appeared on Joe Rogan's podcast on July 13, 2023 -- episode #2008. Meyer has a PhD in the History and Philosphy of Science and if you pay any attention to him at all, it will soon become apparent that he really knows his stuff. He has a slow and stammering style, however, so listen to him at 1.5x speed.
I have been following Meyer since the late 1990s and I have read his books and watched his debates online, etc. As far as I am concerned, Meyer is undefeated in any public conversation that I have seen him engage in and I have never read a convincing rebuttal to the arguments he makes in his books (Signature in the Cell, Darwin's Doubt, and The Return of the God Hypothesis).
I find Meyer to be a far more credible and far more serious intellectual force than the various academics and intellectuals that are associated with the other side of the debate. I don't think Dawkins has an answer to the question of the origin of life, I don't think Neil DeGrasse Tyson is a serious thinker, I don't find the multiverse nonsense credible at all, and the various physicists who push it are just making fools of themselves, in my view.
You asked about a protein whose origin cannot be explained through the Darwinian story. I am only going to be relaying arguments that have been made by Stephen Meyer and Douglas Axe, so I would suggest you listen to them make those arguments directly.
You can hear Doug Axe summarize the problem if you go to YouTube and find video "qwFi_2YZa_c"
If you listen to JRE #2008, starting at 13:30, you will hear Joe Rogan ask a normie question "doesn't it work if you just give it enough time" and the Meyer responds with an argument I find convincing. I will summarize it here:
We now know, thanks to the genetic revolution, that if you want to build a new form of life you have to have new code, because new anatomical structures require new cell types, whih require new proteins which can only be created by a protein that is one step further back in the process, i.e., the code. So if you're going to have a cell that functions in a digestive system, it is going to have to have an associated enzyme to to perform the digestive function, which means that it going to have to have different RNA.
So you have a situation in which you need to have an enzyme evolve, but the enzye is created by a sequence of code, so to iterate on the enzyme as you are evolving it you can't directly mutate it, but you have to mutate the code that creates it. The analogy to software is good -- suppose you have a string that doesn't work for some purpose (perhaps it is an incorrect password) and you need to try a different string instead, but instead of copying and mutatatig the string to see if you can get a better one, you have to copy and mutate the function that produces the string. Unfortunately, the relationship between the function that produces the string (which is itself a different string) and the string you're interested in is not direct and by randomly mutating the function you just end up breaking the function altogether pretty much every time.
Another aspect of genetics to consider is developmental gene regulatory networks. It turns out that in addition to genes that build proteins, there are also genes the build molecues that send signals to other parts of the genome. This is why cells can differentiate themselves from each other when they undergo cell division. So as an animal grows from a single fertilized cell into two cells and then four cells and then eventually billions of celles, there is an over-arching plan that can be realized and the fully grown animal can be composed of many different types of organs and tissues. Obviously the timing and accuracy of the orchestration of cell-division is crucial to ending up with all your organs in the right place. What scientists discovered as they studied these developmental gene regulatory networks is that they look to us like integrated circuits (for conducting information) and that they are incredibly tighly integrated. What this means is that if you want to turn body plan A into body plan B, you are going to have to do it by modifying the developmental gene regulatory networks, but these networks are so dense and integrated that you basically cannot modify them without destroying their ability to serve their initial purpose. In other words, you break the first body plan long before you come up with a different body plan.
The fundamental problem that the materialist Darwinian evolution story has is the origin of information. Information is highly specific. You cannot just randomly muck around with it without degrading the signal.