I have had the GT2 Pro and GT3 Active in my hands, the GT5 Pro is a combination of those two with extra features, it has smoother scrolling in the software usage, if Europe allowed NFC payments, it would have no competition... for now it's good but not perfect, it remains a health care watch with Apple Watch Ultra quality and basic smart functions, which is why it has at least a week of battery life.
The battery, with everything activated and an hour of running each day, lasts 5 to 6 days.
Its measurements, although I have no comparison metric, are satisfactory; anyway, smartwatches cannot satisfy and replace medical measuring instruments but can be used as a tool for comparing daily conditions under certain circumstances.
One last observation, strong in hardware and smooth in refresh rate, a watch like the GT5 Pro lasts less than the GT2 Pro, which you had for 12 days in the water. We can't have it all, which is why the truly "smart" Huawei Watch 4 has a larger battery but still lasts the same. It would be great if they had a solar panel like Garmin, even if they cost a bit more.
22/12
With 10 days of use and wearing it almost all day, its battery is very good... with all the sensors active and doing running-type workouts every day using GPS, the battery will last you 6 days at most; otherwise, with moderate use of 2 to 3 gym sessions a week with GPS or simple use, it will definitely last a week. In my case, since 16/12 when I charged it, with two days of running with GPS in the past week, I still have 60%, having used it for a total of about 4 hours at irregular intervals throughout the week.
Coming from an Apple Watch SE 2, which I suspect had a boot loop because I charged it with any charger I found, although I have read that they experience this, I would recommend charging it by connecting it to a PC. The charging cable it has is 5 - 9V 2A and completes in one hour with 10% battery by plugging it into my laptop, which is 5V=5W like all PCs.