I understand that spooky action-at-a-distance magic can really ruin a codebase's maintainability. But what you've developed here is not a judicious appreciation of its danger and its power, but a blanket aversion to both its risks and its benefits.
An apt metaphor would be, let's say: toast. If you try to make some toast, but accidentally burn your house down, it's understandable that you might want to have your bread un-toasted for a while. But it doesn't make sense to switch your diet to be entirely raw as a result, especially if you eat a lot of chicken.
In python, metaprogramming is like fire. People who haven't seen it before are fascinated before it, and try to touch it. This always goes badly. But that doesn't mean it's useless or we shouldn't have it. There are many things it's good for, if it's carefully and thoughtfully applied.
attrs goes out of its way to avoid any behind-the-scenes effects. It even generates Python code, rather than using setattr(), so that if any error happens in the constructor, you can step through it normally in the debugger, and see it in the traceback. Its semantics are clear and direct. It doesn't have these problems.