Apple Watch, verification failed unknown error has occurred

Hello, I just bought this series 5 cellular watch and I’m trying to get it to connect with my iPhone 11 pro. The carrier for the phone doesn’t support the watch so I got a stand-alone plan for it, from us mobile. Because I’m using two different carriers I had to make two different apple ids. US mobile requires you to have two different apple ids and have to connect through family sharing. Every time after I put my password in, it always says verification failed, unknown error has occurred. I’ve been talking to an apple agent for 3 days now and nothing they tell me to do is working. Sometimes the watch would ask me to update it but when I try to do it, says everything is up to date. This is really frustrating. I’ve tried everything and read multiple forms and nothing has helped.