I love my Apple Watch Ultra, and have been using the tech giant’s smartwatches since they debuted in 2015. Throughout that time, they’ve helped me hit new fitness goals every year, whether that’s running further or lifting heavier. The Apple Watch even helped me get medical assistance for an underlying heart issue that would’ve gone undiagnosed without it. The Apple Watch has been a big part of my life during that time, but there’s always been one big flaw – it didn’t know when to quit… Apple Watch’s biggest issuePicture this: You’ve hit a new personal best on, say, running a 10k. Your muscles…