On adding plug, it never completes

Is it the key, like this?

I don’t have those, either. I have only the original Plug “v1” models, which I’ve been using since 2019 (plus some Plug Outdoors that I acquired later).

I’m glad someone else with iOS experience is commenting, because I’m not sure what else to suggest at this point. I got it done using an Android phone last year, like I said, but it was an exercise in frustration.