What Android does is slightly more complicated than that, but it's good to know Apple supports at least something standardized. The main advantage of DPP/EasyConnect (what Android uses with QR codes) is that the key isn't actually stored in the code. It creates a temporary key that allows both devices to communicate securely, then transfers the credentials securely over that connection.

Distributing a public key through a QR code? That's something I did a number of years ago for a similar purpose: https://throwpass.com

And at the end of the story there’s still an unlimited amount of devices that possess the key. So what is the gain?

The key is only useful to the first device that gets it. It's generated for each transaction and only valid once. The devices (let's say two phones) communicate directly and once that's done, the connection closes. To add another device, the phone weill generate a new key and a new QR code.

Yeah that’s great but at the end of the story each phone has the PSK because that’s what it uses to actually connect to the wireless network.

I can't get this to work, because my SSID is the poo emoji. I'm not sure what character encoding QR codes use, and I haven't really bothered trying to debug this.

QR codes, like SMS messages, can use multiple encodings. This avoids wasting space. Unfortunately utf8 is not one of the encodings so although there are tricks to encode utf8 anyway they are not supported by all scanners.

Perhaps this standard allows specifying the BSSID instead, somehow?

Next step is daily cycling of the password and an e-ink display with the QR code!