I just had the exact same experience. My Versa 4 was just over a year but less than 18 months old. This issue started maybe 2 months ago when this thread began, and I restarted the device a dozen times, performed 2 factory resets, checked to make sure the app and firmware were the latest version, and removed/reconnected the device on the app twice (so it's pretty clearly a firmware issue like everyone else's). Battery level was always above 70 to 80%, but it always shut off whenever I began a run or started a timer, and the only way to turn it back on was to connect it to the charger.
Customer support said it was past the warranty, to which I replied that's understandable but there doesn't seem to be anything wrong with the device itself and I still expect decent software support for more than 12 months after purchase. He didn't offer any further assistance targeting the software/firmware after asking if I had restarted the watch.
I even spoke to a manager and explained that I'm a Fitbit Premium user and this is the 3rd Fitbit device I've owned. He said "unfortunately, we use a warranty system, so the 35% discount is all I can offer you." Yeah buddy, everybody uses a warranty system, and we're all aware how they work. Good companies still hold their products and services to a basic standard of quality and intervene whenever something misses the mark. Good customer service departments also know that I spend more on my annual Premium subscription than they were trying to get me to pay for a new watch (which only would have been $98 after the discount). I told him I wasn't going to buy a new watch at any price but wanted to make it clear that his company had gotten me to buy 3 different devices over 7 years and remain subscribed to a $9.99/mo subscription after the trial--which is the entire goal of a software company's marketing department--but if I have to throw this watch in the trash then I'm never spending another dollar on Fitbit. He was okay with that. I had already canceled my Fitbit Premium subscription before we hung up, and the watch went in the trash can before I sat up from my chair.
At the end of the day, I wouldn't have been particularly optimistic even if they had sent me a brand new Versa 4. The device itself doesn't have a problem, just like everyone else's device on this thread. And Fitbit doesn't seem to have any sort of direct answer or solution to the software problem. So I could have waited weeks to get the new device only to experience the same issues and been back at square one. I wasn't trying to get a new watch out of Fitbit...I only wanted to be able to use the working watch I already had, and it was a huge red flag that they didn't have any answers on that front.
