Telstra couldn't even tell me whether they were still in conversation with Apple to resolve issues. I think that I read somewhere that iPhone8 Plus still has issues... but I could be wrong.
I have to retrieve my friends phone again and call ALDI Mobile. One hopes that there's a dialogue happening between some of the 3 players in this.
As for remote diagnostics no, but did discuss the settings and have performed multiple reboots and a reset of network settings, although I can't see how that would help. There was a suggestion that the phone may have a hardware issue that needed repair, but that would be one H-word of a co-incidence. Nowhere near an Apple outlet of any kind here, but I think that would be a long shot in any event.
Friend's SIM works in my iPhone 14 Pro, but my SIM does not get the iPhone X back on the air.
So, ALDI Mobile next, but the eeyore in me thinks that'll be a bust too.
More to come. :-)