Go for a short ride in turbo, or lift the rear off the ground and put a cable-tie round the handlebar switch to engage walk mode (make sure the pedals are clear and it's secure!) - this takes a lot longer than a short ride in turbo. Anything less than 80% would be my aim.
The Amazfit is great for tracking time/distance metrics plus a downloadable GPS track, but AFAIK it only shows the battery % of the watch, not your bike. If you can get it to show bike battery level please post how.
Buy a mechanical 24hr timer and charge it for the recommended time before you ride, that's what I do. Bike gets charged to 60% after a ride and stored. On the night before a ride I set the timer for 2hrs starting at 6am (5hrs is a full charge, so to add another 40% needs 2hrs).
100% means it's fully charged, anything else is pretty irrelevant. Just like the rest of the bike won't be like new - brake fluid, chain/gears, suspension, bearings - all used but it still works OK for most of us so 100% ready to go until things need replacing or break.
Weather vanes point to the direction the wind is blowing from, so that stupid app mimics a weather vane showing the wind is from the SW i.e. a south-westerly which blows towards the NE . . just saying.
I've done 3,000km trouble free in 2 yrs on my H15.
The rear hub problem was down to a batch of sub-standard hubs used when they had supply problems with the standard one.
The frame crack seems to have affected a small number of bikes, but the lifetime guarantee sorts that out. It's not an euro...
There is no downside apart from unknown long term issues - same or better spec cf existing new models at that price WRT frame and weight, with bigger battery and more power. What else comes close?
You're higher up so not breathing much of what the wheels kick up, and millions of years of evolution means your lungs can cope with "normal" dust (asbestos, maybe not so much . .).
Why, when manufacturers say store at 60-80% ?
Charging to 100% allows the cells to balance for optimum range and performance. Charging to less amplifies small differences between cells which may mean individual cells get a deep discharge which isn't good.
I always charge to 60-70% because that's what Shimano say to store at, so it doesn't matter if I don't ride it for a few days, and also if I forget to charge, or the timer fails, or if I don't have time I can still go straight out for a decent ride.
Edible if prepared correctly, and hallucinogenic - allegedly Viking Beserkers ate them before going mental. Might be worth eating before trying a triple black DH route . .