Looking thru the Monster Manual, the number of creatures that are of concern for doublechecking Strength Athletics are few.
Mainly the culprits are the statblocks that represent reallife animals, which we can objectively critique for nonmagical traits. Among these statblocks only some of the Tiny ones and even fewer among the Small ones are off.
Many of the Tiny and Small Beasts with low Strength, really do have low Strength even for their Size. They dont feature remarkable Athletics nor Weightlifting.
With regard to Strength, the Medium and larger animals are moreorless what they are. Those animals that are known for their Strength like Lion, Ox, Bear, are strong, even for their Size.
With regard to Dexterity, in reallife the most dexterous species in existence appears to be Homo sapiens. This species adapted for a unique dependence on tool usage. The capacity for object manipulation and precision is unsurpassed. Comparing the nearest related species, bonobo and chimpanzee, one can see how the freed hands, with opposing thumbs, wrapping pinkies, and pivoting wrists, and with regard to object manipulation, readily demonstrate how the sapiens is more dexterous in every way. The bonobo and the chimpanzee are agile, brachiating among trees and exhibiting superhuman climbing and jumping Strength Athletics skill. Chimpanzee are about 1.35 to 1.5 times stronger than the sapiens, depending on the task. Bonobos are remarkable at jumping. Yet even these close relatives fall out of trees and break their bones, often enough. The sapiens mastery of dexterity and precision informs every aspect of sapiens behavior, even beyond the use of the specialized limbs, involving modes of cognition.
With regard to the D&D Beast statblocks, the Dexterity and Wisdom Scores tend to be grossly inflated.
The Human has among the best eyesight among all species, including color vision, parallax distance judgment, and so on. Even so, a few other animals have features to see what Humans dont. Many animals have superior hearing and olfaction. The olfaction of the canines is extraordinary and preternatural.
The Beast statblock should often have an innate Expertise in Perception checks that rely on sound or scent or so on, but they shouldnt have high "wisdom", per se.
With regard to Dexterity inflation, the situation is hilarious.
Consider how the most dexterous reallife species on the planet, the Human, exhibits an "average" of Dexterity +0 (Score 10).
Now consider the Seahorse in the Monster Manual. This Tiny Beast with a single Hit Point is listed as if having a Dexterity +1 (Score 12) that is as if superior to the average Human. It is impossible for a Seahorse to have a Dexterity +1. It has a prehensile tail, but it mainly coils around something to anchor itself in place, and is obviously less Dexterity than a Human hand. Meanwhile with regard to Athletics, it is an extremely poor swimmer, especially for its Size. Among the slowest creatures on the planet is a species of seahorse, with a top speed of about 5 feet per hour. The Seahorse males rarely venture beyond the space of a cubic meter for their entire lives, and the females rarely beyond 100 meters. The Seahorse survives by camouflaging, staying still, and ambushing tinier things that swim by.
The Seahorse deserves Stealth Expertise, with a Camouflage trait. But its Dexterity Sleight manipulation is low and its precision is unexceptional. Generously, the Dexterity Score is about 6, at most 7. Tho its Strength (Athletics or Weightlifting) probably really is −5 (Score 1). The Seahorse might be a good example of what Strength Score 1 looks like, and not because it is Tiny.
Yet the grotesque habit of inflating low Strength creatures with stupidly high Dexterity affects most Tiny creatures, even when preposterous.
The Octopus is said to have Dexterity +2 (Score 15). At best, the Dexterity of an Octopus is equal to a Human, but the Human is better. Probably the Octopus deserves a Dexterity −1 (Score 8). An Octopus can open the lid of a jar, for example. (And is intelligent enough to learn how to do it.) At the same time, the Octopus exhibits preternatural camouflage. It needs Stealth Expertise, Stealth Advantage, and perhaps even an Invisibility ability when keeping still. But the Human is more dexterous.
Agility − swimming, jumping, climbing, running − skillfully or strenuously − is Strength Athletics. It has nothing to do with Dexterity.