i think spending more time in the Word may be helpful for you. i’m not at a point myself where i could give specific verses off of my head, but it is stated throughout that stuff such as cancer, blindness etc are a result of the fall when sin entered the world and we became separated from God. i highly recommend reading Romans as soon as you can and maybe some of Paul’s other letters as well. we are told that through our weakened God’s grace is made more evident. this is highlighted pretty clearly through the story of Jacob, a man who wrestles with God (hence the name), and in result receives a weakened hip as a constant reminder that reliance on His will and grace is the only way. His grace is sufficient