@p11, I suspect @WildBill’s suggestion may be at least part of the solution, just based on my own experience with various IoT devices (from non-Wyze manufacturers). I’m using Android but recently had an experience where an original Plug seemed to conk out after I added a new access point to my network (so the Plug issue may or may not have been coincidental):
I think the key is going to be to make any 5 GHz network connection completely unavailable to your iPhone so that it’s forced to use a 2.4 GHz Wi-Fi connection. That’s what I’ve had to do in order to get many IoT things online and configured. Once the device has been setup, you can re-enable your 5 GHz Wi-Fi so that your phone (and other things capable of using that frequency) can be happy.
My guess is that the iPad might have a pre-v2.45x app version. Note this: