2nd hand Apple Watch 6 stuck in “signing into your account”

Hi there I purchased an Apple Watch 6 from another user but I’m having trouble pairing it. I’m not sure what they did to prepare it for sale. I get to the screen on my iphone that says “signing into your account” and then it gets stuck there. I’ve tried resetting the phone. My iOS is up-to-date. My Bluetooth and wifi and cellular are all good. The watch even show up as connected in my Bluetooth. But it won’t sign in. I’ve tried three different peoples phones and Apple IDs to to rule out an issue with the phone. And all three have had the same issue with this watch. I’ve tried resetting the watch by pressing and holding both buttons down. I don’t have any opetikn on the watch. Watch just says. “Please continue in your phone”. ( I don’t have the original device or Apple ID of the former owner to be able signs in and reset the watch from the app). And I’ve talked to 7 different apple support agents and done all the ‘articles’ that I can. Is there anything I can do, Apple can do, or the former owner can do (no longer an apple user) to get it to work? Tia