is it possible its been locked out of the telus network ? Lol....like the opposite of being locked to a network? Is this even possible? @sheytoon do you know anything on this subject?
What you allude to is the whitelisting of IMEIs before a device can register onto the network with a particular SIM. As far as I know, no Canadian carrier has ever had a requirement for devices to be "white-listed" before they can be used. This is something that Verizon (and possibly Sprint) does (IMEI must be recognized/certified to work on their network before it's allowed to register onto it with a Verizon SIM).
Update... my Bell SIM no longer works in this iPhone XR. I haven't re-tested the Rogers SIM yet, but this leads me to think their is something physically wrong with the phone.
I tried a Koodoo SIM today with no luck. I'm going to re-try a Rogers SIM again for entertainment purposes, but I think my next stop is to the Apple store to see if they can confirm if their is a hardware issue related to the cell/network part of the phone.
Your assessment is very reasonable, based on your update (as are suggestions about it being black-listed, which are plausible). If it's not black-listed, then it sounds like maybe an intermittent issue with the radio (hopefully not), or antenna connection (a bit easier to overcome, if it's a popped connector for example).
The ability to connect on Rogers might suggest a stronger signal or tower in closer proximity (compared to Telus tower), so that even with impaired antenna, it's connecting. But, without details, that's just speculation.