Remember, the 6 D&D attributes are trash for actually simulating anything about real world human capabilities.
They have been watered down in many ways, but IME they actually can cover every thing, if properly and broadly defined, comprised of multiple elements.
Dexterity, for example, throughout the editions includes these elements:
In 1E: hand-eye coordination, agility, reflexes, precision, balance, speed of movement
In 2E: hand-eye coordination, agility, reaction speed, reflexes, balance
In 3E: hand-eye coordination, agility, reflexes, balance
in 4E: hand-eye coordination, agility, reflexes, balance
In 5E: agility, reflexes, balance
Elements which are missing but often appear in other games include: bodily grace and flexibility, and probably many others which could comprise "dexterity". But with each edition more elements were removed...
Other ability scores have shifted parts of their meaning from one ability score to a different one, which for people playing from one edition to another might have confusion.
If we examine a definition for each element currently in 5E:
Agility:
the power of moving quickly and easily; nimbleness
Reflexes:
a sudden, automatic reaction to something
Balance:
the ability to retain a state of equilibrium or equipoise
and for
Dexterity:
flexibility, ease, and speed in the use of the hands or body
Now, if you follow definitions deeply enough, agility would include flexibility and bodily control, so what contortionists would use IMO.
Their only fault IME is they don't distinguish beween their elements when a person, creature, whatever has a particular score. They lack granularity. Is a creature with DEX 20, with a +5 modifier, super agile, have great reflexes, or phenomenal balance? Is it great at all three? Could a creature with DEX 14 effectively be agility +1, reflexes +0, and balance +5, for an
average of +2, does it have to be +2 across the board??