I looked your question over,,here is my opinion:
I agree with your husband,,that said let me continue.
The first thing you say is that the oil warning light was
flickering at idle,,but then you never tell us how much oil pressure there was,,before,,you install a new oil pressure sender.
Now i believe that you car idles at about 900 rpm,,and if the oil pressure light was flickering at 900 rpm,,then there is 1 of 3 possible scenarios, a. the engine is not idling at 900 rpm's and the tachometer is faulty. b. the oil pressure sender is faulty. c. the engine is idling at 900 rpm's,,the oil sender is not faulty and the engine is low on oil and is worn out.
Everything that you are describing is the making of a worn tired engine.
I read about all of those parts that you,,or that you had replaced,,but what i do not read is that any of the old parts were worn out and,,needed,,to be replaced.
What i see is a whole lot of guessing and throwing in of money in the once in a million chance that maybe someone will get lucky and get the right part replaced.
I sure as hell hope that you didn't have to pay any out of pocket money for all of the dealer " Advising " to replace this part or that part,,when they were using your car as a laboratory experiment or as an on the job teaching aid.