Hi there, I also want to get this sorted.
I had the idea when I went to the Gallery of the Shortcuts app and found that you could turn your wifi network into a QR code. once scanned, you'll be prompted to join the network. (ignore the one comment in this threat saying you can't scan a QR code to connect to wifi networks...)
the only app I found with the most functionality when it comes to writing on NFC tags is NFC Tools (https://apps.apple.com/au/app/nfc-tools/id1252962749).
right toward the bottom, there's an option to "Configure a Wi-Fi Network" and I've tried every possible combination of Authentication (Open, WPA-Personal, Shared, WPA-Enterprise, WPA2- Enterprise, WPA2-Personal, WPA/WPA2-Personal) and Encryption (None, WEP, TKIP, AES, AES/TKIP), but when I scan the NFC Tag it just doesn't do anything. At the very least you'd expect a prompt like a pull tab from the top to acknowledge and approve the action, but nada.
For my own sanity, I tried scanning it with a friend's Samsung device and (feign surprise) a prompt was shown to join the network.
For now though, I'm choosing "Add email record" so it prompts the user to compose an email, and the body just contains the SSID and password. I'll explore App Clips as well because that might be promising? A nice little lightweight way to hopefully interact with NFC Tags.
I'm sending this as feedback as well because the whole Shortcuts, NFC, and 'deeper dive mentality' feels like an afterthought when it comes to cases like these. It would be phenomenal if we could create automations with NFC tags for more than just your own devices (if that makes sense?) because right now I need to create a shortcut, share it with all the family members and friends that have iPhones, and then set up automations for all of them to run that shortcut when the NFC tag is scanned.