There is no way you will have network coverage on your phone at 35.000 ft
Still for me there are to many coincidences that and chain of events must have been really overwhelming, that the failures caused the aircraft to become invisible and silent, at the most convenient moment of the flight!
I do not believe the pilots are at blame, maybe it is a combination of unknown factors, as I can't see how a modern T7 could suffer such a failure - in that case it will be a latent failure, also existing on other T7's, and there will be no rest by the authorities and Boeing until something has been found!
There is no way with current available information to put together any even remotely satisfactory chain of events that can explain what happen, based on the facts that we are aware of at this moment.
I do believe some more information is known, and I also believe at the moment we can't even be certain of the current search area being the correct one.
All this uber-info about Pings and Arcs and various explanations means very little, as we have not been presented with all the data required to make such analyses.