I added Apple App Clip but later removed it not yet needed. It was added "Advanced App Clip Experience", later deactivated, but when you bring the NFC tag to the phone, an alert still pops up with an empty content and message "This app clip is not currently available in your country or region".
I had the same problem. The fix was to ensure that the App Clip Experience was deactivated in App Store Connect.
I submitted a binary/build that contained an App Clip to Testflight so that I could access the Advance App Clip settings.
Deactivated the App Clip Experience (your step #1)
Waited a day to account for the caching system, and now, after testing, scanning my QR Code (in your case, it would be triggering the event with the NFC tag) produces the correct results.
It is important to note that even though you may have a live app that does not contain an App Clip, you must still deactivate it in Advance App Clip.