Just went through a similar "life throws a curveball at you" situation.
Wasn't my job, but my wife's. She had to go on disability and with it, an income that rivalled mine.
Had an '18 5th wheel that we owed money on. Had a '14 Ram 3500 with only 42000Km's on it that was paid for.
Managed to sell the 5th for what we still owed on it. Thankful for that.
Had just purchased an RV lot that has proven to be very therapeutic for DW's condition, so we wanted to hang on to it if at all possible. Problem: no trailer.
Sold the Ram and used its funds to buy a destination trailer. Problem solved, but now I don't have a truck.
After making some other adjustments to our finances/lifestyle it looks like things should work out OK.
In retrospect though, if I had waited a bit to see what some of the uncertainties would actually have looked like I most likely would have been able to keep the truck. Like yours, it wasn't being utilized to it's potential at the time, but who knows what the future may have held for it?
Maybe if you get a job buyout then you could pay off your truck?
Guess what I'm saying is that maybe a "step back and breathe" moment might be worth the time. I went through my situation with a "OK, let's get this plan in motion and not waiver". Yes, it did work out, but it may have worked out a bit differently/better perhaps if I'd taken a moment to pause.
As for the last Mega you mentioned. It may be OK, but buying a deleted truck that someone else has had the controls of the tuner over would worry ME a bit.
Not sure if this rambling is helpful, but thought I'd just relay my recent experience.
All the best,
Mike