Try reaching to their email/chat. I've been having a different issue and they told me to do a factory reset, but I've seen many reports before yours, and told them I'd never do that unless I have some kind of assurance I'd get a new one in case it got stuck in this kind of login-update-stucked kind of loop.
Hey guys! This is actually something we've been seeing with a number of people.
I do want to let it be known that we do have an open thread in regards to this where you can stay up to date on any official updates that may come through.
Feel free to post any information or other possible steps you might have there!