Honestly, most if not all companies advertising offline LLMs in mobile devices/wearables are either rebranding regular algorithms as a flashy 'AI' or use incredibly small models that you wouldn't want to rely on anyways, especially related to health.
I would personally go with something common and reliable if I actually care about my health and didn't want to just see random numbers. I wanted to go with either Garmin or some fitness Xiaomi/Huawei watch that don't require internet.
I ended up having Apple watch connected to very old and broken iphone that I bought for cheap. It's only used for updates and (as a bonus) a payment card pushing, as well as health data syncing when needed (AW shows all the info locally and offline anyways).