There are two of them, one under CONNECT/CHAT SETTINGS,
other under ACCESSIBILITY/VISUAL.
As I understand, ACCESSIBILITY is just repeate collection of related options for easy adjust.
Both should be 0-100 scale
Issue is, the one under ACCESSIBILITY has different scaling from the main one, and no indication in descriptive text that it should have or why.
Adjusting the main scale to 100 moves the ACC to 255
Adjusting the ACC one manually to max sets it to 100 and the main one goes to 39
Adjusting the main scale to 50 moves the ACC to 130
Adjusting the ACC one to 50 sets the main one to 19
etc
Confusing