There is a book on this forum site: [URL removed]
The book claims it is well documented and explored that myopic eye enlargement is from stretching or decrease of density of ocular structures, and not growth or new cell formation.
Then, I come to conclusions.
Why choroid thins? The sclera stretches.
Why the sclera stretches? Because of mechanical tension.
What is capable to produce tension, to say stretch or un-stretch the sclera? Extrinsic muscles, intraocular pressure, maybe ciliary muscle.
Defocus theory can’t explain why I get slightly more myopic refraction after sleeping.
Mechanical theory, yes.
Eyes cross when I falling asleep while looking down or not up.
Crossed eyes produce accommodation.
Accommodation tenses up ciliary muscle.
There is a positive relation between ciliary muscle and oblique muscles.
Prolonged or chronic contraction of the last results in gradual increase in axial length, like chronic winking by first increases astigmatism only temporarily, then permanently.
That is what I collected during my research.
Certainly, these are only hypotheses or predications.
But, the documentation you cited seem to be also too one-sided or incomplete, because it lacks the view of eye as a whole, omitting how all those processes relate to each other.