You could aim to use well-known ideas to explain errors or deny anything meaningful is going on. The benefit to that is that you don’t have to investigate all that much and you can move on to other errors. What if you find a lot of errors are the same that you brushed aside tho? Those are random too? Or they’re not really explainable? There’s a cap to this approach.
What’s in the quote above is what you should aim for. What is it? One part is to “actually understand what’s going on in more depth”. That’s learning about an underlying issue. You can understand that an error is caused by another underlying error. You can investigate to find that you might have a bias or conceptual misconception. You may find that a thinking process is causing unlimited mistakes. If you didn’t understand what was going on in depth, then I think you wouldn’t get some processes used involved in your error.
That part of the approach sounds like more work, but it has a bigger payoff. It’s something to be more knowledgeable about. There’s more to learn about. Postmortems seem like one of the only ways to engage with underlying lying errors. It’s one of the ways to understand causes of mistakes and fixing them a lot of them.
The last part of the quote about what you should aim for is “and fix it in a lasting, effective way.” Fixing what’s going on in a lasting, effective way sounds good. Postmortems are lasting cuz you addressed the cause of some of your mistakes. You literally get why you made many of your mistakes and now you resolved the reason you make them. That’s gonna last for sure. Also, I think you should aim for effective changes cuz you could be focusing on the small stuff too much and not make any progress. This could lead one to quit.