Sure, you could do that an get some people to fall for that. But in the end, you can just call them stupid for scanning random qr codes and then entering private information. No involvement by Apple.

An airtag is a product by a big company, claiming to be trustworthy. Claiming their products are safe. You are actually told by Apple to scan those airtags, made by them. So you find an Apple airtag, scan it with your Apple iPhone, and an Apple login form is presented to you. Way, way different from that qr code scenario.