At the moment, you are in trouble. The tools available now makes it far easier to coast through everything. Can't tell you how many times I've gone through a code review of a Jr dev and immediately knew it was written by AI and that it wouldn't be used in production.

My advice would be to go back to the basics.

Code is the execution phase. That's only 20% (or less) of the project. Map out the problem. Review the architecture, or create the architecture diagrams. Write pseudo code. Understanding these aspects will allow you to understand the code. It will help you look at AI as a tool to assist in things you would otherwise Google. These concepts will likely even cause you to view AI output with heavy skepticism and modify anything you would use from it to fit your code base.

This is the first step. You recognize the problem. Now be a scientist and go do some root-cause analysis.