An average adult male’s hand is 7.6” (inches) and an average female’s hand is 6.8” (inches). My hand size is 6.2” (inches).
Imagine there is a circle around your hand and move this circle to the neck of your guitar. If you try to stretch outside of your circumference, you will damage yourself.
There is another technique:
Plant your thumb securely on the back of the neck and play the 5th fret on the A string. With your thumb locked down, lift two of your fingers and then pivot to the 10th fret. You’re “swiveling” off of your thumb to the 10th fret. This is called, “the swivel technique.”
I have taught hundreds of students. People with hands bigger or smaller hands than mine and lefties and righties. The guitar is hard for everyone! Guitar stretches are not the only technique that exists. To be an excellent guitar player, you have to master all of the techniques.