Evolution is a very inefficient process. It is extremely wasteful, and it does not need to be efficient because it has plenty of time to refine bad designs. However, this does not imply that evolution is incapable of producing animals. In fact, it only needs to make things that are good enough, and good enough is often far from the best.
One of the major issues with evolution is that it frequently results in animals with poor vision. This is due to the fact that vision is such a complex trait, and if a creature had decent eye sight but, because of new changes in the environment, didnโt require good vision to survive over time, resulting in poor vision, it also might happen that the environment changes again and now good vision is required to get the best changes for survival.
So many times, animals donโt get much time to adjust themselves, resulting in extinction, so it picks good enough things in a random pile of randomness.
Why evolution is bad at making animals
Another problem with evolution is that it can lead to animals with deformities or diseases. This is because mutations are random, and sometimes they can have negative consequences for the animal. For example, there are many diseases that are caused by mutations in genes. These diseases wouldnโt exist if it werenโt for evolution.
Finally, another problem with evolution is that it can take a long time for new traits to evolve. This means that an animal might not be able to adapt to its environment as quickly as other animals, which have already evolved the necessary traits. For example, if there was a change in the climate, some animals would die out because they wouldnโt be able to adapt quickly enough, while others would thrive because they would already have the right traits for the new climate.
But understand that evolution is a system that relies on the environment, and the environment changes very randomly, so itโs obvious that some great potential might not live another day, and badly optimized designs may live for billions of years, and it might be that there has been an animal that has better potential for occupying the planet intelligently than the human itself. But we will never know, because itโs not about the best design, itโs about good enough. And thatโs why evolution is bad at making animals.
Evolution doesnโt need to do its best.

Also understand that its not about best it about what a creature needs that can help them in their survival and sometimes less is more. So a mutation might seem bad but in actuality it can be helpful, for example: webbed feet help a creature move through water faster which can be the difference between getting away from a predator or being eaten.
So when we think about how evolution is โbadโ at making animals we have to remember that its not about making the best possible animal, its about making an animal that is good enough to survive and reproduce.
Overall, evolution is a very inefficient process, but it doesnโt need to be efficient because it has a lot of time to refine bad designs. It only needs to make things that are good enough, and good enough is often far from the best.