65 Chapter 13 records Job’s charges against his friends for the way they used their knowledge (1–5), his warning that God would find out their insincerity (6–12), and his pleading of his cause to God in which he begs for God to remove his hand from him and that he would not terrify him with his majesty and that he would reveal the sins that caused such great suffering (13–28).
1 Hebrew has כֹּל (kol, “all”); there is no reason to add anything to the text to gain a meaning “all this.”

In other versions

“Behold, my eye has seen all this,

my ear has heard and understood it.

“My eyes have seen all this,

my ears have heard and understood it.

Look, my eyes have seen all this;

my ears have heard and understood it.

“Look, I have seen all this with my own eyes

and heard it with my own ears, and now I understand.

“Look, my eye has seen everything;

my ear has heard and has understood it.

Lo, mine eye hath seen all this,

Mine ear hath heard and understood it.

Public Domain

Job 13:1