From standard Darwin literature:

https://www.sciencedirect.com/science/article/abs/pii/S0079610722000347

Astract
"Darwinian evolution is a nineteenth century descriptive concept that itself has evolved. Selection by survival of the fittest was a captivating idea. Microevolution was biologically and empirically verified by discovery of mutations. There has been limited progress to the modern synthesis. The central focus of this perspective is to provide evidence to document that selection based on survival of the fittest is insufficient for other than microevolution....However, macroevolution (required for all speciation events and the complexifications appearing in the Cambrian explosion) are shown to be probabilistically highly implausible (on the order of 10−50) when based on selection by survival of the fittest. We conclude that macroevolution via survival of the fittest is not salvageable by arguments for random genetic drift and other proposed mechanisms. Evolutionary biology is relevant to cancer mechanisms with significance beyond academics. We challenge evolutionary biology to advance boldly beyond the inadequacies of the modern synthesis toward a unifying theory modeled after the Grand Unified Theory in physics. This should include the possibility of a fifth force in nature. Mathematics should be rigorously applied to current and future evolutionary empirical discoveries. We present justification that molecular biology and biochemistry must evolve to aeon (life) chemistry that acknowledges the uniqueness of enzymes for life. To evolve, biological evolution must face the known deficiencies, especially the limitations of the concept survival of the fittest,"

From the article: "Survival of the fittest is adequate to select for such changes (gains) which occur within one genome primarily by single fixed mutations (and perhaps sometimes by horizontal gene transfer). Macroevolution, however, requires major changes necessitating multiple changes that logically most frequently occur in multiple genomes....… Thus, survival of the fittest is illogical when proposed as adequate for selecting the origination of all complex, major, new body-types and metabolic functions because the multiple changes in multiple genomes that are required have intermediate stages without advantage; selection would not reasonably occur, and disadvantage or death would logically prevail."

ID coment: "What they are saying is that when some feature requires multiple changes before providing an increase in fitness, the changes cannot be produced by mutation and selection alone. Their subsequent comments, almost sound like an implicit endorsement of intelligent design."

From the article: "It is our perspective that the burden is too great for survival of the fittest to select evolutionary changes that accomplish all evolutionary novelty. Thus, evolution lacks a sufficient mechanism for multifactorial selections because a process that looks forward, is nonrandom, deterministic, or occurs by an unknown biological process, is required. The position of mainstream biologists regarding this aspect of evolution is that nature is always non-purposeful and, therefore, the proposed selection (process, force, tendency), could not possibly be natural (scientific). However, our perspective is that this is a supposition of necessity rather than an established principle. Logic demands that it be open to investigation. This first requires an openness to ideas and science must be open to new ideas. "

ID comment: " They thus propose that evolution is only possible if it is “nonrandom, deterministic, or occurs by an unknown biological process” — something that some would reluctantly conclude “could not possibly be natural.”

From the article: Darwin wrote in On the Origin of Species… : “If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case.” Today, Darwin’s missing cases are abundant including each complex transition to a new body type, metabolic cycle, or metabolic chain. Multi-step processes are routinely required at every evolutionary step." (my bold)

Final ID blow: "They use a case study of the origin of the Krebs cycle — a metabolic pathway involving 12 enzymes that is necessary for life. They believe that this is a useful test for evolution. They assume that the genome is “ripe” to produce each enzyme where a minimal number of mutations is needed for a gene to suddenly become functional. They therefore choose an incredibly generous value of 0.00001 as the probability that a given enzyme can be created by a single mutation."

"They calculate the likelihood of producing all 12 enzymes needed to produce a selectable function as 10-51. They note this is below 10-50, a probability that was called “negligible” by Émile Borel, the French mathematician, who stated “this process of evolution involves certain properties of living matter that prevent us from asserting that the process was accomplished in accordance with the laws of chance.'”

Comment: the authors' opinions follqw mine as expressed here. Every de novo phenotypical or biochemical appearance is a gap. No itty-bitty Darwinoid steps. My bolds emphasize these points. With designed gaps, a designer must exist.