In 2020, it seemed like the Oura Ring was everywhere. Researchers were studying whether the smart ring (and other wearables) could one day detect illness, and right on cue, the NBA announced it bought 2,000 Oura Rings to monitor athletes. Prince Harry has been a fan for years, and celebrities like Jennifer Aniston and Kim Kardashian West have also been spotted wearing the sleep tracker. That’s already a lot of buzz for a niche gadget, but the third-generation Oura Ring, which launched in…