I would have thought the small filter you installed would have closed off as well if there had been a lot of junk coming from the tank. Is it possible you just have a glow plug problem?

Just a coincidental failure but the episode on the trip a couple of days earlier might have fixated you too much. If you got fuel at all injectors when loosening the hard lines you may want to check the glow circuit.

Still the injectors as you mentioned could be gunked up but that would bring up the question what was in that fuel you brought. You fuelled from high volume diesel locations? I always do if at all humanly possible.

Those occasional small volume diesel fuel sellers are always a risk. I had more than enough experiences years ago to stay well away from them.