The Amazfit brand has helped Zepp Health bounce back in a big way after years of negative returns.After several years of losses, Zepp Health Corporation (ZEPP -3.29%) took off in 2025. The manufacturer of smart wearable technology is up over 1,900% on the year, as of Oct. 16, and most of that growth came during the last three months. That's much better than Apple, the leader in wearable devices, which has lost about 1%.What turned around Zepp Health's performance? One strategic shift has made all the differ ...