Are you working on a team? I've found that for solo projects this works but, even when you own the design of your piece, integrating with the work of several people doing this ultimately leads to even the part you initially designed no longer working exactly as you remember it.
A good chunk of my time now is spend working with an LLM to understand how other parts of the code base work and how they relate to and interact with the product features I manage. But I'm still on a small enough team that this is possible. I'm not surprised at all that an engineer at an org the size of Meta would not even be able to perform this level of work in understanding what's happening.
Are you working on a team? I've found that for solo projects this works but, even when you own the design of your piece, integrating with the work of several people doing this ultimately leads to even the part you initially designed no longer working exactly as you remember it.
A good chunk of my time now is spend working with an LLM to understand how other parts of the code base work and how they relate to and interact with the product features I manage. But I'm still on a small enough team that this is possible. I'm not surprised at all that an engineer at an org the size of Meta would not even be able to perform this level of work in understanding what's happening.