If there were “alien technology” our military, congress, and gov’t bureaucracy would have long ago disclosed/sold it to our adversaries for personal profit. Heck, Biden would have skimmed his 10% already, and Hunter would be on the board of “intergalactic crackpipes, inc”
I have no doubt Col. Nell might believed what he is saying, but he wouldnt be the first person placed in a position as a useful idiot in charge of a fake operation he was too dumb to figure out was not what he was told it was.
Your theory may be right or it may be wrong. But it is still just a theory and vulnerable to change as more information comes in.