Yea, that is what gets me too, when I look at the blockers to use; Ad blockers have access to all keystrokes, forms and pages. They have access to my banking and other codes when I use them .
While I am sure the more popular blockers do not abuse this, and the code most likely checked line by line. It’s still possible for a handful of mistakes to allow supply chain attacks or a dozen other things to happen.
It worries me, so I don’t use them as extension and use security elsewhere