I’ve had an Arya V2 once die on me with the same issue and out of Hifiman warranty. I wrote Hifiman support and they offered me to send the defect pair in and they’d replace it with a new one for 450$ + shipping.
In my case I found out that my dealer had a longer warranty than Hifiman themselves so I got a free replacement via the dealer but in your case maybe getting a replacement via the support might be a possible solution. You’d just end up with a current production stealth version probably.
Still a bitter pill to swallow but maybe better than a 900€ paper weight you can’t really use for anything?