Samsung Flip5, android, rural/remote area.

Had an interesting case of *hot-spot failure* that several hours of
discussion with the (Telus) supplier's help desk was unable to solve!
I'm new to smart-phones and use mine for mainly 2 things, these being
its reason for existance: internet hot-spot and possible outgoing
emergency calls. The contract says XY gb's of data per month at high
rate and the rest at low. Because of topography and antenna distribution
the low-rate never works but the high one usually got me up to 4-5 Mb/s.
During times of medium to heavy precipitation in the direction of what I
suspect is the source antenna (about 50 km over water) reception starts
to falter. Last month I maxed out the quota so were it not for my wife's
phone I would have ended up with no internet for 4 days. Time for the beef.

All of a sudden, no connection, so next day I got on the blower and they
guided me step-by-step through TS for quite a while, none of it
resulting in any kind of fix. My wife's phone continued delivering so
the issue was in or with mine. We broke for lunch and then I had the
idea to do a factory reset, which worked. I'd like to FIND the actual
cause and be able to repeatedly DUPLICATE the problem so as to avoid it
in the future, hence this post.

I'd appreciate a short list of possible suspects although to my way of
thinking IF I am able to select hot-spot ON then there should be nothing
else to do or not do on the phone-side. If there is then the hot-spot
slider should be ghosted (which it never was).