Oh yeah, definitely sounds like it's something that's worth a crack - but which one of our intrepid UA carriers wants to volunteer (possibly) to die? They also might need someone to hold their UA while they prepare a freshly unwrapped Sidey to swap into...
Although re-reading your post, I notice that you provide a way simply to test the degradation theory... Which doesn't require a UA...
First they should make a jump without sacrificing their drive, just as i have described a few posts back.
Sap 8 and UA in cargo, and then a maximum possible jump (around 30 LY?)
I kind of like the miss jump idea, but I don't quite see how it fits with the morse.
Perhaps we enter a new kind of space and can jettison there?
also explained that, but here you go:
Based on the lore, the Thargoids were not aggressive. They tried to communicate with us.
But we attacked them, we ignored the attempts.
Then we got a communication device, but it was never used (political reasons, why communicating when you can get more followers by winning a war? build a huge army to defeat them?).
The Thargoids vanished and were never seen again.
Thats why i assume that the Witchspace is their home, its the biggest space there is and it would explain why we cant find them.
The UA sends Morse code as we know allready, but have you never wondered why it spells our Planetnames? Why do the Thargoids even know OUR names?
Thats why i think the UA is such a communicator, it accesses OUR ships computer and translates it into thargoid-morse, since they allready have a way to translate from Thargoid to Human.
Why dont they just talk to us? Maybe they assumed that we allready know what they want - communication, but we dont have the device to talk to them, so thats why they are sending them to us for basic translation.