Stock loss harvesting is a matter of selling for the short term, waiting the necessary time, and then buying it again.
Is that what you mean to do? It sounds like you are just looking to sell, and move on.
Boeing no doubt blew a strategic product positioning advantage over Airbus, which had to shoot its white elephant, the A380. But comical as they both are, they are still a duopoly. And air travel demand has come back very strong with the lifting of Covid restrictions, which anyone who flew this summer could tell you.
Boeing's problem is not lack of demand, which is one of the few things they don't control. If your time horizon is long enough, it seems like a good turnaround candidate.