I've noticed that too, once you get an initial implementation it seems to always find a way to argue for keeping that approach in the name of simplicity

Like "Let's stick with what we have, its simple and it works." or "That seems overkill, let's not over complicate things"

I've got to the point where sometimes I frame my question as if I disagree with it, just to allow the AI to "agree" with me and actually critique it.

"My team mate wants to X, but I feel like that might be a bad idea. What could go wrong?", etc.

In this vein, I have a system level memory for Claude to push back and give me direct feedback when possible. So far a success as it helps cut through the sycophancy.