I would be OK with it if it lasted all day and recharge at night but it doesn't.
I have been searching the net and it doesn't look like the battery is replaceable. It is a Apple knockoff and there is no way to open the case.
And in fact there doesn't seem to be much information on it at all.
The instructions were so small that I had to photograph them and then expand the picture to read them. Nothing on the battery.
Most phones don't have replaceable batteries these days. I don't think any smart watches do. The problem is to get the power density within the form factor they can't use off-the-shelf batteries and replaceable sockets so the battery is basically a chip soldered to the board in the sealed housing.
To be blunt with what we've all been saying, there's nothing you can do with that watch. It is functioning as designed: it parted someone with their money. That it even turns on after the money makes it's way to southeast asia is irrelevant to the maker or seller.